18811816 has 8 divisors (see below), whose sum is σ = 35272170. Its totient is φ = 9405904.

The previous prime is 18811813. The next prime is 18811831. The reversal of 18811816 is 61811881.

It can be written as a sum of positive squares in only one way, i.e., 11249316 + 7562500 = 3354^2 + 2750^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (18811813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1175731 + ... + 1175746.

Almost surely, 2^18811816 is an apocalyptic number.

It is an amenable number.

18811816 is a deficient number, since it is larger than the sum of its proper divisors (16460354).

18811816 is a wasteful number, since it uses less digits than its factorization.

18811816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2351483 (or 2351479 counting only the distinct ones).

The product of its digits is 3072, while the sum is 34.

The square root of 18811816 is about 4337.2590422985. The cubic root of 18811816 is about 265.9562744944.

The spelling of 18811816 in words is "eighteen million, eight hundred eleven thousand, eight hundred sixteen".