91615345920 has 576 divisors, whose sum is σ = 380235018240. Its totient is φ = 20451336192.

The previous prime is 91615345919. The next prime is 91615345951. The reversal of 91615345920 is 2954351619.

91615345920 is a `hidden beast` number, since 9 + 1 + 6 + 1 + 53 + 4 + 592 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 10398157 + ... + 10406963.

It is an arithmetic number, because the mean of its divisors is an integer number (660130240).

Almost surely, 2^91615345920 is an apocalyptic number.

91615345920 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91615345920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190117509120).

91615345920 is an abundant number, since it is smaller than the sum of its proper divisors (288619672320).

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

91615345920 is a wasteful number, since it uses less digits than its factorization.

91615345920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8887 (or 8867 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The spelling of 91615345920 in words is "ninety-one billion, six hundred fifteen million, three hundred forty-five thousand, nine hundred twenty".