81560656 has 20 divisors (see below), whose sum is σ = 160704000. Its totient is φ = 40088672.

The previous prime is 81560639. The next prime is 81560657. The reversal of 81560656 is 65606518.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81560657) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42256 + ... + 44143.

It is an arithmetic number, because the mean of its divisors is an integer number (8035200).

Almost surely, 2^81560656 is an apocalyptic number.

It is an amenable number.

81560656 is a deficient number, since it is larger than the sum of its proper divisors (79143344).

81560656 is a wasteful number, since it uses less digits than its factorization.

81560656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86466 (or 86460 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 37.

The square root of 81560656 is about 9031.0938429406. The cubic root of 81560656 is about 433.6708555113.

The spelling of 81560656 in words is "eighty-one million, five hundred sixty thousand, six hundred fifty-six".