18751816 has 32 divisors (see below), whose sum is σ = 37490040. Its totient is φ = 8762368.

The previous prime is 18751813. The next prime is 18751819. The reversal of 18751816 is 61815781.

It is an interprime number because it is at equal distance from previous prime (18751813) and next prime (18751819).

It can be written as a sum of positive squares in 4 ways, for example, as 18748900 + 2916 = 4330^2 + 54^2 .

It is not an unprimeable number, because it can be changed into a prime (18751813) 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, 23130 + ... + 23926.

Almost surely, 2^18751816 is an apocalyptic number.

It is an amenable number.

18751816 is a deficient number, since it is larger than the sum of its proper divisors (18738224).

18751816 is a wasteful number, since it uses less digits than its factorization.

18751816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993 (or 989 counting only the distinct ones).

The product of its digits is 13440, while the sum is 37.

The square root of 18751816 is about 4330.3367074628. The cubic root of 18751816 is about 265.6732188542.

It can be divided in two parts, 187 and 51816, that added together give a triangular number (52003 = T₃₂₂).

The spelling of 18751816 in words is "eighteen million, seven hundred fifty-one thousand, eight hundred sixteen".