91681656 has 64 divisors (see below), whose sum is σ = 251164800. Its totient is φ = 27657600.

The previous prime is 91681627. The next prime is 91681721. The reversal of 91681656 is 65618619.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70371 + ... + 71661.

It is an arithmetic number, because the mean of its divisors is an integer number (3924450).

Almost surely, 2^91681656 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 91681656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125582400).

91681656 is an abundant number, since it is smaller than the sum of its proper divisors (159483144).

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

91681656 is a wasteful number, since it uses less digits than its factorization.

91681656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1580 (or 1576 counting only the distinct ones).

The product of its digits is 77760, while the sum is 42.

The square root of 91681656 is about 9575.0538379687. The cubic root of 91681656 is about 450.9144466637.

The spelling of 91681656 in words is "ninety-one million, six hundred eighty-one thousand, six hundred fifty-six".