91430991 has 16 divisors (see below), whose sum is σ = 136322400. Its totient is φ = 60562944.

The previous prime is 91430987. The next prime is 91431007. The reversal of 91430991 is 19903419.

It is not a de Polignac number, because 91430991 - 2² = 91430987 is a prime.

It is a super-2 number, since 2×91430991² = 16719252230484162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91430921) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 6546 + ... + 15023.

It is an arithmetic number, because the mean of its divisors is an integer number (8520150).

Almost surely, 2^91430991 is an apocalyptic number.

91430991 is a deficient number, since it is larger than the sum of its proper divisors (44891409).

91430991 is a wasteful number, since it uses less digits than its factorization.

91430991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21735 (or 21729 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 91430991 is about 9561.9553962566. The cubic root of 91430991 is about 450.5031261550.

The spelling of 91430991 in words is "ninety-one million, four hundred thirty thousand, nine hundred ninety-one".