91687728 has 40 divisors (see below), whose sum is σ = 258394176. Its totient is φ = 27784000.

The previous prime is 91687679. The next prime is 91687733. The reversal of 91687728 is 82778619.

It is a Harshad number since it is a multiple of its sum of digits (48).

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 7 ways as a sum of consecutive naturals, for example, 86298 + ... + 87353.

Almost surely, 2^91687728 is an apocalyptic number.

It is an amenable number.

91687728 is an abundant number, since it is smaller than the sum of its proper divisors (166706448).

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

91687728 is a wasteful number, since it uses less digits than its factorization.

91687728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173673 (or 173667 counting only the distinct ones).

The product of its digits is 338688, while the sum is 48.

The square root of 91687728 is about 9575.3709066542. The cubic root of 91687728 is about 450.9244010071.

The spelling of 91687728 in words is "ninety-one million, six hundred eighty-seven thousand, seven hundred twenty-eight".