91790563840 has 320 divisors, whose sum is σ = 240554603520. Its totient is φ = 33492828160.

The previous prime is 91790563831. The next prime is 91790563873. The reversal of 91790563840 is 4836509719.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (320).

It is a super-2 number, since 2×91790563840² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 113461356 + ... + 113462164.

It is an arithmetic number, because the mean of its divisors is an integer number (751733136).

Almost surely, 2^91790563840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91790563840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120277301760).

91790563840 is an abundant number, since it is smaller than the sum of its proper divisors (148764039680).

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

91790563840 is a wasteful number, since it uses less digits than its factorization.

91790563840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 943 (or 927 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 52.

The spelling of 91790563840 in words is "ninety-one billion, seven hundred ninety million, five hundred sixty-three thousand, eight hundred forty".