18977640 has 96 divisors (see below), whose sum is σ = 62627040. Its totient is φ = 4597120.

The previous prime is 18977639. The next prime is 18977723. The reversal of 18977640 is 4677981.

It is a junction number, because it is equal to n+sod(n) for n = 18977592 and 18977601.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13867 + ... + 15173.

It is an arithmetic number, because the mean of its divisors is an integer number (652365).

Almost surely, 2^18977640 is an apocalyptic number.

18977640 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 18977640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31313520).

18977640 is an abundant number, since it is smaller than the sum of its proper divisors (43649400).

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

18977640 is a wasteful number, since it uses less digits than its factorization.

18977640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1343 (or 1328 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 42.

The square root of 18977640 is about 4356.3333205805. Note that the first 4 decimals coincide. The cubic root of 18977640 is about 266.7354475357.

The spelling of 18977640 in words is "eighteen million, nine hundred seventy-seven thousand, six hundred forty".