91891615533 has 32 divisors (see below), whose sum is σ = 130849966080. Its totient is φ = 57161583360.

The previous prime is 91891615489. The next prime is 91891615589. The reversal of 91891615533 is 33551619819.

It is a de Polignac number, because none of the positive numbers 2^k-91891615533 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91891615033) 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 31 ways as a sum of consecutive naturals, for example, 2750298 + ... + 2783508.

It is an arithmetic number, because the mean of its divisors is an integer number (4089061440).

Almost surely, 2^91891615533 is an apocalyptic number.

It is an amenable number.

91891615533 is a deficient number, since it is larger than the sum of its proper divisors (38958350547).

91891615533 is a wasteful number, since it uses less digits than its factorization.

91891615533 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33697.

The product of its digits is 874800, while the sum is 51.

The spelling of 91891615533 in words is "ninety-one billion, eight hundred ninety-one million, six hundred fifteen thousand, five hundred thirty-three".