18712865 has 4 divisors (see below), whose sum is σ = 22455444. Its totient is φ = 14970288.

The previous prime is 18712849. The next prime is 18712867. The reversal of 18712865 is 56821781.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14348944 + 4363921 = 3788^2 + 2089^2 .

It is a cyclic number.

It is not a de Polignac number, because 18712865 - 2⁴ = 18712849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18712867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1871282 + ... + 1871291.

It is an arithmetic number, because the mean of its divisors is an integer number (5613861).

Almost surely, 2^18712865 is an apocalyptic number.

It is an amenable number.

18712865 is a deficient number, since it is larger than the sum of its proper divisors (3742579).

18712865 is an equidigital number, since it uses as much as digits as its factorization.

18712865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3742578.

The product of its digits is 26880, while the sum is 38.

The square root of 18712865 is about 4325.8369132458. The cubic root of 18712865 is about 265.4891404890.

The spelling of 18712865 in words is "eighteen million, seven hundred twelve thousand, eight hundred sixty-five".