18990920 has 64 divisors (see below), whose sum is σ = 46872000. Its totient is φ = 6882048.

The previous prime is 18990919. The next prime is 18990931. The reversal of 18990920 is 2909981.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30371 + ... + 30989.

It is an arithmetic number, because the mean of its divisors is an integer number (732375).

Almost surely, 2^18990920 is an apocalyptic number.

18990920 is a gapful number since it is divisible by the number (10) 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 18990920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23436000).

18990920 is an abundant number, since it is smaller than the sum of its proper divisors (27881080).

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

18990920 is a wasteful number, since it uses less digits than its factorization.

18990920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 702 (or 698 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 38.

The square root of 18990920 is about 4357.8572716416. The cubic root of 18990920 is about 266.7976509290.

The spelling of 18990920 in words is "eighteen million, nine hundred ninety thousand, nine hundred twenty".