18815920 has 20 divisors (see below), whose sum is σ = 43747200. Its totient is φ = 7526336.

The previous prime is 18815917. The next prime is 18815921. The reversal of 18815920 is 2951881.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18815921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 117520 + ... + 117679.

It is an arithmetic number, because the mean of its divisors is an integer number (2187360).

Almost surely, 2^18815920 is an apocalyptic number.

18815920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18815920 is an abundant number, since it is smaller than the sum of its proper divisors (24931280).

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

18815920 is a wasteful number, since it uses less digits than its factorization.

18815920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235212 (or 235206 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 18815920 is about 4337.7321263536. The cubic root of 18815920 is about 265.9756134954.

The spelling of 18815920 in words is "eighteen million, eight hundred fifteen thousand, nine hundred twenty".