91993531 has 12 divisors (see below), whose sum is σ = 109035072. Its totient is φ = 77361648.

The previous prime is 91993519. The next prime is 91993543. The reversal of 91993531 is 13539919.

It is an interprime number because it is at equal distance from previous prime (91993519) and next prime (91993543).

It is not a de Polignac number, because 91993531 - 2⁹ = 91993019 is a prime.

It is a super-2 number, since 2×91993531² = 16925619491695922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91993501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15115 + ... + 20308.

It is an arithmetic number, because the mean of its divisors is an integer number (9086256).

Almost surely, 2^91993531 is an apocalyptic number.

91993531 is a deficient number, since it is larger than the sum of its proper divisors (17041541).

91993531 is a wasteful number, since it uses less digits than its factorization.

91993531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35490 (or 35483 counting only the distinct ones).

The product of its digits is 32805, while the sum is 40.

The square root of 91993531 is about 9591.3258207612. The cubic root of 91993531 is about 451.4251623652.

The spelling of 91993531 in words is "ninety-one million, nine hundred ninety-three thousand, five hundred thirty-one".