18978244 has 24 divisors (see below), whose sum is σ = 34401528. Its totient is φ = 9154560.

The previous prime is 18978241. The next prime is 18978251. The reversal of 18978244 is 44287981.

It can be written as a sum of positive squares in 4 ways, for example, as 160000 + 18818244 = 400^2 + 4338^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18978244.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18978241) 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, 15312 + ... + 16504.

It is an arithmetic number, because the mean of its divisors is an integer number (1433397).

Almost surely, 2^18978244 is an apocalyptic number.

It is an amenable number.

18978244 is a deficient number, since it is larger than the sum of its proper divisors (15423284).

18978244 is a wasteful number, since it uses less digits than its factorization.

18978244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1335 (or 1333 counting only the distinct ones).

The product of its digits is 129024, while the sum is 43.

The square root of 18978244 is about 4356.4026443845. The cubic root of 18978244 is about 266.7382772957.

The spelling of 18978244 in words is "eighteen million, nine hundred seventy-eight thousand, two hundred forty-four".