81161656 has 32 divisors (see below), whose sum is σ = 157418640. Its totient is φ = 39207168.

The previous prime is 81161653. The next prime is 81161657. The reversal of 81161656 is 65616118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81161653) 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, 26980 + ... + 29836.

Almost surely, 2^81161656 is an apocalyptic number.

It is an amenable number.

81161656 is a deficient number, since it is larger than the sum of its proper divisors (76256984).

81161656 is a wasteful number, since it uses less digits than its factorization.

81161656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2983 (or 2979 counting only the distinct ones).

The product of its digits is 8640, while the sum is 34.

The square root of 81161656 is about 9008.9764124455. The cubic root of 81161656 is about 432.9625172233.

The spelling of 81161656 in words is "eighty-one million, one hundred sixty-one thousand, six hundred fifty-six".