91999889631 has 48 divisors (see below), whose sum is σ = 146582532096. Its totient is φ = 55244524608.

The previous prime is 91999889591. The next prime is 91999889633. The reversal of 91999889631 is 13698899919.

It is not a de Polignac number, because 91999889631 - 2⁷ = 91999889503 is a prime.

It is a super-2 number, since 2×91999889631² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 91999889631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91999889633) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5460286 + ... + 5477108.

It is an arithmetic number, because the mean of its divisors is an integer number (3053802752).

Almost surely, 2^91999889631 is an apocalyptic number.

91999889631 is a deficient number, since it is larger than the sum of its proper divisors (54582642465).

91999889631 is a wasteful number, since it uses less digits than its factorization.

91999889631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17972 (or 17969 counting only the distinct ones).

The product of its digits is 68024448, while the sum is 72.

The spelling of 91999889631 in words is "ninety-one billion, nine hundred ninety-nine million, eight hundred eighty-nine thousand, six hundred thirty-one".