91977721480 has 64 divisors (see below), whose sum is σ = 207467568000. Its totient is φ = 36699193344.

The previous prime is 91977721457. The next prime is 91977721483. The reversal of 91977721480 is 8412777919.

It is not an unprimeable number, because it can be changed into a prime (91977721483) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40571307 + ... + 40573573.

It is an arithmetic number, because the mean of its divisors is an integer number (3241680750).

Almost surely, 2^91977721480 is an apocalyptic number.

It is an amenable number.

91977721480 is an abundant number, since it is smaller than the sum of its proper divisors (115489846520).

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

91977721480 is a wasteful number, since it uses less digits than its factorization.

91977721480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4366 (or 4362 counting only the distinct ones).

The product of its (nonzero) digits is 1778112, while the sum is 55.

The spelling of 91977721480 in words is "ninety-one billion, nine hundred seventy-seven million, seven hundred twenty-one thousand, four hundred eighty".