91331640428 has 12 divisors (see below), whose sum is σ = 182663280912. Its totient is φ = 39142131600.

The previous prime is 91331640383. The next prime is 91331640457. The reversal of 91331640428 is 82404613319.

91331640428 is an admirable number.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1630922123 + ... + 1630922178.

It is an arithmetic number, because the mean of its divisors is an integer number (15221940076).

Almost surely, 2^91331640428 is an apocalyptic number.

It is an amenable number.

91331640428 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91331640428 is a wasteful number, since it uses less digits than its factorization.

91331640428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3261844312 (or 3261844310 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 41.

The spelling of 91331640428 in words is "ninety-one billion, three hundred thirty-one million, six hundred forty thousand, four hundred twenty-eight".