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81992620 = 2254199991
BaseRepresentation
bin1001110001100…
…01101110101100
312201021122201201
410320301232230
5131442230440
612045215244
72013632353
oct470615654
9181248651
1081992620
11423122a6
1223561524
1313caa358
14ac6499a
1572e919a
hex4e31bac

81992620 has 24 divisors (see below), whose sum is σ = 176385888. Its totient is φ = 31996800.

The previous prime is 81992609. The next prime is 81992621. The reversal of 81992620 is 2629918.

It is a self number, because there is not a number n which added to its sum of digits gives 81992620.

It is not an unprimeable number, because it can be changed into a prime (81992621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49176 + ... + 50815.

It is an arithmetic number, because the mean of its divisors is an integer number (7349412).

Almost surely, 281992620 is an apocalyptic number.

It is an amenable number.

81992620 is an abundant number, since it is smaller than the sum of its proper divisors (94393268).

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

81992620 is a wasteful number, since it uses less digits than its factorization.

81992620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100041 (or 100039 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 81992620 is about 9054.9776366372. The cubic root of 81992620 is about 434.4351147414.

It can be divided in two parts, 819 and 92620, that added together give a palindrome (93439).

The spelling of 81992620 in words is "eighty-one million, nine hundred ninety-two thousand, six hundred twenty".

Divisors: 1 2 4 5 10 20 41 82 164 205 410 820 99991 199982 399964 499955 999910 1999820 4099631 8199262 16398524 20498155 40996310 81992620