91971972 has 72 divisors (see below), whose sum is σ = 249945696. Its totient is φ = 28410624.

The previous prime is 91971953. The next prime is 91972007. The reversal of 91971972 is 27917919.

It is a super-3 number, since 3×91971972³ (a number of 25 digits) contains 333 as substring.

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 23 ways as a sum of consecutive naturals, for example, 39883 + ... + 42125.

It is an arithmetic number, because the mean of its divisors is an integer number (3471468).

Almost surely, 2^91971972 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 91971972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124972848).

91971972 is an abundant number, since it is smaller than the sum of its proper divisors (157973724).

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

91971972 is a wasteful number, since it uses less digits than its factorization.

91971972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2337 (or 2332 counting only the distinct ones).

The product of its digits is 71442, while the sum is 45.

The square root of 91971972 is about 9590.2018748304. The cubic root of 91971972 is about 451.3898952643.

The spelling of 91971972 in words is "ninety-one million, nine hundred seventy-one thousand, nine hundred seventy-two".