18974781 has 24 divisors (see below), whose sum is σ = 31449600. Its totient is φ = 10799136.

The previous prime is 18974779. The next prime is 18974783. The reversal of 18974781 is 18747981.

It is an interprime number because it is at equal distance from previous prime (18974779) and next prime (18974783).

It is not a de Polignac number, because 18974781 - 2¹ = 18974779 is a prime.

It is a super-2 number, since 2×18974781² = 720084627995922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18974783) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21556 + ... + 22418.

It is an arithmetic number, because the mean of its divisors is an integer number (1310400).

Almost surely, 2^18974781 is an apocalyptic number.

It is an amenable number.

18974781 is a deficient number, since it is larger than the sum of its proper divisors (12474819).

18974781 is a wasteful number, since it uses less digits than its factorization.

18974781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1225 (or 1222 counting only the distinct ones).

The product of its digits is 112896, while the sum is 45.

The square root of 18974781 is about 4356.0051652862. The cubic root of 18974781 is about 266.7220522111.

Subtracting from 18974781 its sum of digits (45), we obtain a 4-th power (18974736 = 66⁴).

The spelling of 18974781 in words is "eighteen million, nine hundred seventy-four thousand, seven hundred eighty-one".