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81556740 = 22335197949
BaseRepresentation
bin1001101110001…
…11010100000100
312200110111211000
410313013110010
5131334303430
612032013300
72010135516
oct467072404
9180414730
1081556740
1142044871
1223391230
1313b86b35
14ab8dbb6
15725ee60
hex4dc7504

81556740 has 96 divisors (see below), whose sum is σ = 267120000. Its totient is φ = 20601216.

The previous prime is 81556723. The next prime is 81556751. The reversal of 81556740 is 4765518.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81556695 and 81556704.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6286 + ... + 14234.

It is an arithmetic number, because the mean of its divisors is an integer number (2782500).

Almost surely, 281556740 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81556740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133560000).

81556740 is an abundant number, since it is smaller than the sum of its proper divisors (185563260).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81556740 is a wasteful number, since it uses less digits than its factorization.

81556740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7986 (or 7978 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The square root of 81556740 is about 9030.8770338212. The cubic root of 81556740 is about 433.6639147373.

The spelling of 81556740 in words is "eighty-one million, five hundred fifty-six thousand, seven hundred forty".

Divisors: 1 2 3 4 5 6 9 10 12 15 18 19 20 27 30 36 38 45 54 57 60 76 90 95 108 114 135 171 180 190 228 270 285 342 380 513 540 570 684 855 1026 1140 1710 2052 2565 3420 5130 7949 10260 15898 23847 31796 39745 47694 71541 79490 95388 119235 143082 151031 158980 214623 238470 286164 302062 357705 429246 453093 476940 604124 715410 755155 858492 906186 1073115 1359279 1430820 1510310 1812372 2146230 2265465 2718558 3020620 4077837 4292460 4530930 5437116 6796395 8155674 9061860 13592790 16311348 20389185 27185580 40778370 81556740