91511621 has 4 divisors (see below), whose sum is σ = 91599744. Its totient is φ = 91423500.

The previous prime is 91511599. The next prime is 91511627. The reversal of 91511621 is 12611519.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91511621 - 2¹⁴ = 91495237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91511627) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42485 + ... + 44586.

It is an arithmetic number, because the mean of its divisors is an integer number (22899936).

Almost surely, 2^91511621 is an apocalyptic number.

It is an amenable number.

91511621 is a deficient number, since it is larger than the sum of its proper divisors (88123).

91511621 is a wasteful number, since it uses less digits than its factorization.

91511621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88122.

The product of its digits is 540, while the sum is 26.

The square root of 91511621 is about 9566.1706549695. The cubic root of 91511621 is about 450.6355152360.

The spelling of 91511621 in words is "ninety-one million, five hundred eleven thousand, six hundred twenty-one".