91990100 has 18 divisors (see below), whose sum is σ = 199618734. Its totient is φ = 36796000.

The previous prime is 91990097. The next prime is 91990109. The reversal of 91990100 is 109919.

It can be written as a sum of positive squares in 3 ways, for example, as 4343056 + 87647044 = 2084^2 + 9362^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91990109) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 459851 + ... + 460050.

Almost surely, 2^91990100 is an apocalyptic number.

It is an amenable number.

91990100 is an abundant number, since it is smaller than the sum of its proper divisors (107628634).

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

91990100 is a wasteful number, since it uses less digits than its factorization.

91990100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 919915 (or 919908 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 91990100 is about 9591.1469595664. The cubic root of 91990100 is about 451.4195501627.

It can be divided in two parts, 919 and 90100, that added together give a palindrome (91019).

The spelling of 91990100 in words is "ninety-one million, nine hundred ninety thousand, one hundred".