18977920 has 64 divisors (see below), whose sum is σ = 48880440. Its totient is φ = 7004160.

The previous prime is 18977911. The next prime is 18977939. The reversal of 18977920 is 2977981.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 12787776 + 6190144 = 3576^2 + 2488^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×18977920² = 720322895052800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7180 + ... + 9460.

Almost surely, 2^18977920 is an apocalyptic number.

18977920 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 18977920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24440220).

18977920 is an abundant number, since it is smaller than the sum of its proper divisors (29902520).

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

18977920 is a wasteful number, since it uses less digits than its factorization.

18977920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2313 (or 2301 counting only the distinct ones).

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 18977920 is about 4356.3654575804. The cubic root of 18977920 is about 266.7367593525.

The spelling of 18977920 in words is "eighteen million, nine hundred seventy-seven thousand, nine hundred twenty".