91531872 has 72 divisors (see below), whose sum is σ = 263292120. Its totient is φ = 30159360.

The previous prime is 91531837. The next prime is 91531879. The reversal of 91531872 is 27813519.

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

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91531879) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23847 + ... + 27417.

It is an arithmetic number, because the mean of its divisors is an integer number (3656835).

Almost surely, 2^91531872 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 91531872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131646060).

91531872 is an abundant number, since it is smaller than the sum of its proper divisors (171760248).

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

91531872 is a wasteful number, since it uses less digits than its factorization.

91531872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3676 (or 3665 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 91531872 is about 9567.2290659313. The cubic root of 91531872 is about 450.6687538077.

It can be divided in two parts, 9153 and 1872, that added together give a square (11025 = 105²).

The spelling of 91531872 in words is "ninety-one million, five hundred thirty-one thousand, eight hundred seventy-two".