90991220418 has 90 divisors (see below), whose sum is σ = 230150514867. Its totient is φ = 25979574600.

The previous prime is 90991220417. The next prime is 90991220423. The reversal of 90991220418 is 81402219909.

90991220418 is a `hidden beast` number, since 9 + 0 + 9 + 9 + 1 + 220 + 418 = 666.

It can be written as a sum of positive squares in only one way, i.e., 45495610209 + 45495610209 = 213297^2 + 213297^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=213297.

It is not an unprimeable number, because it can be changed into a prime (90991220413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 62708593 + ... + 62710043.

Almost surely, 2^90991220418 is an apocalyptic number.

90991220418 is a gapful number since it is divisible by the number (98) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 90991220418

90991220418 is an abundant number, since it is smaller than the sum of its proper divisors (139159294449).

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

90991220418 is an frugal number, since it uses more digits than its factorization.

90991220418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2938 (or 1463 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The spelling of 90991220418 in words is "ninety billion, nine hundred ninety-one million, two hundred twenty thousand, four hundred eighteen".