18816640 has 32 divisors (see below), whose sum is σ = 44985060. Its totient is φ = 7526400.

The previous prime is 18816619. The next prime is 18816667. The reversal of 18816640 is 4661881.

It can be written as a sum of positive squares in 2 ways, for example, as 17239104 + 1577536 = 4152^2 + 1256^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a junction number, because it is equal to n+sod(n) for n = 18816596 and 18816605.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14061 + ... + 15340.

Almost surely, 2^18816640 is an apocalyptic number.

18816640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18816640 is an abundant number, since it is smaller than the sum of its proper divisors (26168420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18816640 is an equidigital number, since it uses as much as digits as its factorization.

18816640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29420 (or 29408 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 18816640 is about 4337.8151182364. The cubic root of 18816640 is about 265.9790060126.

The spelling of 18816640 in words is "eighteen million, eight hundred sixteen thousand, six hundred forty".