91072728 has 32 divisors (see below), whose sum is σ = 252980400. Its totient is φ = 30357504.

The previous prime is 91072727. The next prime is 91072739. The reversal of 91072728 is 82727019.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 91072692 and 91072701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91072727) 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, 210601 + ... + 211032.

Almost surely, 2^91072728 is an apocalyptic number.

It is an amenable number.

91072728 is an abundant number, since it is smaller than the sum of its proper divisors (161907672).

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

91072728 is a wasteful number, since it uses less digits than its factorization.

91072728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421648 (or 421638 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 91072728 is about 9543.2032358113. The cubic root of 91072728 is about 449.9139390978.

The spelling of 91072728 in words is "ninety-one million, seventy-two thousand, seven hundred twenty-eight".