18978738 has 16 divisors (see below), whose sum is σ = 38840736. Its totient is φ = 6179040.

The previous prime is 18978733. The next prime is 18978761. The reversal of 18978738 is 83787981.

It is not an unprimeable number, because it can be changed into a prime (18978733) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36523 + ... + 37038.

It is an arithmetic number, because the mean of its divisors is an integer number (2427546).

Almost surely, 2^18978738 is an apocalyptic number.

18978738 is an abundant number, since it is smaller than the sum of its proper divisors (19861998).

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

18978738 is a wasteful number, since it uses less digits than its factorization.

18978738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73609.

The product of its digits is 677376, while the sum is 51.

The square root of 18978738 is about 4356.4593421723. The cubic root of 18978738 is about 266.7405916575.

The spelling of 18978738 in words is "eighteen million, nine hundred seventy-eight thousand, seven hundred thirty-eight".