18565640 has 16 divisors (see below), whose sum is σ = 41772780. Its totient is φ = 7426240.

The previous prime is 18565639. The next prime is 18565681. The reversal of 18565640 is 4656581.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 15856324 + 2709316 = 3982^2 + 1646^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18565640.

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, 232031 + ... + 232110.

Almost surely, 2^18565640 is an apocalyptic number.

18565640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18565640 is an abundant number, since it is smaller than the sum of its proper divisors (23207140).

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

18565640 is a wasteful number, since it uses less digits than its factorization.

18565640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464152 (or 464148 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 18565640 is about 4308.7863720542. The cubic root of 18565640 is about 264.7910539963.

The spelling of 18565640 in words is "eighteen million, five hundred sixty-five thousand, six hundred forty".