18978772 has 12 divisors (see below), whose sum is σ = 34657056. Its totient is φ = 9076760.

The previous prime is 18978769. The next prime is 18978779. The reversal of 18978772 is 27787981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978779) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103054 + ... + 103237.

It is an arithmetic number, because the mean of its divisors is an integer number (2888088).

Almost surely, 2^18978772 is an apocalyptic number.

It is an amenable number.

18978772 is a deficient number, since it is larger than the sum of its proper divisors (15678284).

18978772 is a wasteful number, since it uses less digits than its factorization.

18978772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206318 (or 206316 counting only the distinct ones).

The product of its digits is 395136, while the sum is 49.

The square root of 18978772 is about 4356.4632444220. The cubic root of 18978772 is about 266.7407509441.

It can be divided in two parts, 189 and 78772, that added together give a square (78961 = 281²).

The spelling of 18978772 in words is "eighteen million, nine hundred seventy-eight thousand, seven hundred seventy-two".