90990720 has 96 divisors (see below), whose sum is σ = 314222220. Its totient is φ = 24262656.

The previous prime is 90990707. The next prime is 90990727. The reversal of 90990720 is 2709909.

It can be written as a sum of positive squares in 2 ways, for example, as 90782784 + 207936 = 9528^2 + 456^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×90990720² = 16558622252236800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (90990727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2139 + ... + 13658.

Almost surely, 2^90990720 is an apocalyptic number.

90990720 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 90990720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (157111110).

90990720 is an abundant number, since it is smaller than the sum of its proper divisors (223231500).

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

90990720 is a wasteful number, since it uses less digits than its factorization.

90990720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15822 (or 15807 counting only the distinct ones).

The product of its (nonzero) digits is 10206, while the sum is 36.

The square root of 90990720 is about 9538.9055976040. The cubic root of 90990720 is about 449.7788543021.

The spelling of 90990720 in words is "ninety million, nine hundred ninety thousand, seven hundred twenty".