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81698816 = 2139973
BaseRepresentation
bin1001101111010…
…10000000000000
312200201201201002
410313222000000
5131403330231
612035031132
72011266653
oct467520000
9180651632
1081698816
1142131591
122343b4a8
1313c066c4
14abc989a
15728c0cb
hex4dea000

81698816 has 28 divisors (see below), whose sum is σ = 163404042. Its totient is φ = 40845312.

The previous prime is 81698807. The next prime is 81698863. The reversal of 81698816 is 61889618.

It can be written as a sum of positive squares in only one way, i.e., 79138816 + 2560000 = 8896^2 + 1600^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3206 + ... + 13178.

Almost surely, 281698816 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 81698816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81702021).

81698816 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81698816 is an frugal number, since it uses more digits than its factorization.

81698816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9999 (or 9975 counting only the distinct ones).

The product of its digits is 165888, while the sum is 47.

The square root of 81698816 is about 9038.7397351622. The cubic root of 81698816 is about 433.9155902012.

The spelling of 81698816 in words is "eighty-one million, six hundred ninety-eight thousand, eight hundred sixteen".

Divisors: 1 2 4 8 16 32 64 128 256 512 1024 2048 4096 8192 9973 19946 39892 79784 159568 319136 638272 1276544 2553088 5106176 10212352 20424704 40849408 81698816