81565260 has 48 divisors (see below), whose sum is σ = 261010176. Its totient is φ = 18643392.

The previous prime is 81565259. The next prime is 81565273. The reversal of 81565260 is 6256518.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96682 + ... + 97521.

It is an arithmetic number, because the mean of its divisors is an integer number (5437712).

Almost surely, 2^81565260 is an apocalyptic number.

It is an amenable number.

81565260 is an abundant number, since it is smaller than the sum of its proper divisors (179444916).

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

81565260 is a wasteful number, since it uses less digits than its factorization.

81565260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194222 (or 194220 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 33.

The square root of 81565260 is about 9031.3487364845. The cubic root of 81565260 is about 433.6790154222.

The spelling of 81565260 in words is "eighty-one million, five hundred sixty-five thousand, two hundred sixty".