91712421 has 12 divisors (see below), whose sum is σ = 135554848. Its totient is φ = 59719464.

The previous prime is 91712393. The next prime is 91712441. The reversal of 91712421 is 12421719.

It is not a de Polignac number, because 91712421 - 2⁹ = 91711909 is a prime.

It is a super-2 number, since 2×91712421² = 16822336331362482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91712441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 118105 + ... + 118878.

Almost surely, 2^91712421 is an apocalyptic number.

It is an amenable number.

91712421 is a deficient number, since it is larger than the sum of its proper divisors (43842427).

91712421 is a wasteful number, since it uses less digits than its factorization.

91712421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237032 (or 237029 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 91712421 is about 9576.6602216013. The cubic root of 91712421 is about 450.9648778046.

The spelling of 91712421 in words is "ninety-one million, seven hundred twelve thousand, four hundred twenty-one".