18977720 has 16 divisors (see below), whose sum is σ = 42699960. Its totient is φ = 7591072.

The previous prime is 18977639. The next prime is 18977723. The reversal of 18977720 is 2777981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18977723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 237182 + ... + 237261.

Almost surely, 2^18977720 is an apocalyptic number.

18977720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18977720 is an abundant number, since it is smaller than the sum of its proper divisors (23722240).

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

18977720 is a wasteful number, since it uses less digits than its factorization.

18977720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474454 (or 474450 counting only the distinct ones).

The product of its (nonzero) digits is 49392, while the sum is 41.

The square root of 18977720 is about 4356.3425026047. The cubic root of 18977720 is about 266.7358223418.

The spelling of 18977720 in words is "eighteen million, nine hundred seventy-seven thousand, seven hundred twenty".