91557690 has 64 divisors (see below), whose sum is σ = 252820224. Its totient is φ = 20786688.

The previous prime is 91557689. The next prime is 91557701. The reversal of 91557690 is 9675519.

It is a super-2 number, since 2×91557690² = 16765621196272200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31582 + ... + 34358.

It is an arithmetic number, because the mean of its divisors is an integer number (3950316).

Almost surely, 2^91557690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91557690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126410112).

91557690 is an abundant number, since it is smaller than the sum of its proper divisors (161262534).

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

91557690 is a wasteful number, since it uses less digits than its factorization.

91557690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2951.

The product of its (nonzero) digits is 85050, while the sum is 42.

The square root of 91557690 is about 9568.5782642982. The cubic root of 91557690 is about 450.7111225543.

The spelling of 91557690 in words is "ninety-one million, five hundred fifty-seven thousand, six hundred ninety".