91220256 has 72 divisors (see below), whose sum is σ = 269038224. Its totient is φ = 30404160.

The previous prime is 91220221. The next prime is 91220287. The reversal of 91220256 is 65202219.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×91220256² = 16642270209411072, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1911 + ... + 13641.

It is an arithmetic number, because the mean of its divisors is an integer number (3736642).

Almost surely, 2^91220256 is an apocalyptic number.

91220256 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91220256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (134519112).

91220256 is an abundant number, since it is smaller than the sum of its proper divisors (177817968).

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

91220256 is a wasteful number, since it uses less digits than its factorization.

91220256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11756 (or 11736 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 91220256 is about 9550.9295882652. The cubic root of 91220256 is about 450.1567453956.

The spelling of 91220256 in words is "ninety-one million, two hundred twenty thousand, two hundred fifty-six".