91901621 has 16 divisors (see below), whose sum is σ = 107864064. Its totient is φ = 76661424.

The previous prime is 91901597. The next prime is 91901627. The reversal of 91901621 is 12610919.

It is not a de Polignac number, because 91901621 - 2¹⁸ = 91639477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91901627) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 151100 + ... + 151706.

It is an arithmetic number, because the mean of its divisors is an integer number (6741504).

Almost surely, 2^91901621 is an apocalyptic number.

It is an amenable number.

91901621 is a deficient number, since it is larger than the sum of its proper divisors (15962443).

91901621 is a wasteful number, since it uses less digits than its factorization.

91901621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 91901621 is about 9586.5333150206. The cubic root of 91901621 is about 451.2747738488.

The spelling of 91901621 in words is "ninety-one million, nine hundred one thousand, six hundred twenty-one".