18981656 has 16 divisors (see below), whose sum is σ = 37684440. Its totient is φ = 8932480.

The previous prime is 18981649. The next prime is 18981661. The reversal of 18981656 is 65618981.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69650 + ... + 69921.

Almost surely, 2^18981656 is an apocalyptic number.

It is an amenable number.

18981656 is a deficient number, since it is larger than the sum of its proper divisors (18702784).

18981656 is a wasteful number, since it uses less digits than its factorization.

18981656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139594 (or 139590 counting only the distinct ones).

The product of its digits is 103680, while the sum is 44.

The square root of 18981656 is about 4356.7942342966. The cubic root of 18981656 is about 266.7542615014.

The spelling of 18981656 in words is "eighteen million, nine hundred eighty-one thousand, six hundred fifty-six".