90215820 has 72 divisors (see below), whose sum is σ = 276529344. Its totient is φ = 23804928.

The previous prime is 90215759. The next prime is 90215833. The reversal of 90215820 is 2851209.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14877 + ... + 20043.

Almost surely, 2^90215820 is an apocalyptic number.

90215820 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 90215820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138264672).

90215820 is an abundant number, since it is smaller than the sum of its proper divisors (186313524).

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

90215820 is a wasteful number, since it uses less digits than its factorization.

90215820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5279 (or 5274 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 90215820 is about 9498.2008822724. The cubic root of 90215820 is about 448.4984023239.

It can be divided in two parts, 9021 and 5820, that added together give a palindrome (14841).

The spelling of 90215820 in words is "ninety million, two hundred fifteen thousand, eight hundred twenty".