18947855 has 4 divisors (see below), whose sum is σ = 22737432. Its totient is φ = 15158280.

The previous prime is 18947849. The next prime is 18947857. The reversal of 18947855 is 55874981.

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

It is not a de Polignac number, because 18947855 - 2²⁴ = 2170639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18947857) 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, 1894781 + ... + 1894790.

It is an arithmetic number, because the mean of its divisors is an integer number (5684358).

Almost surely, 2^18947855 is an apocalyptic number.

18947855 is a deficient number, since it is larger than the sum of its proper divisors (3789577).

18947855 is an equidigital number, since it uses as much as digits as its factorization.

18947855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3789576.

The product of its digits is 403200, while the sum is 47.

The square root of 18947855 is about 4352.9133922007. The cubic root of 18947855 is about 266.5958292747.

The spelling of 18947855 in words is "eighteen million, nine hundred forty-seven thousand, eight hundred fifty-five".