90731888640 has 960 divisors, whose sum is σ = 362376806400. Its totient is φ = 21403533312.

The previous prime is 90731888633. The next prime is 90731888641. The reversal of 90731888640 is 4688813709.

It is a tau number, because it is divible by the number of its divisors (960).

It is a super-2 number, since 2×90731888640² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (90731888641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 714424257 + ... + 714424383.

It is an arithmetic number, because the mean of its divisors is an integer number (377475840).

Almost surely, 2^90731888640 is an apocalyptic number.

90731888640 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 90731888640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181188403200).

90731888640 is an abundant number, since it is smaller than the sum of its proper divisors (271644917760).

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

90731888640 is a wasteful number, since it uses less digits than its factorization.

90731888640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 54.

The spelling of 90731888640 in words is "ninety billion, seven hundred thirty-one million, eight hundred eighty-eight thousand, six hundred forty".