18718906 has 4 divisors (see below), whose sum is σ = 28078362. Its totient is φ = 9359452.

The previous prime is 18718883. The next prime is 18718927. The reversal of 18718906 is 60981781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60981781 = 7 ⋅8711683.

It can be written as a sum of positive squares in only one way, i.e., 14371681 + 4347225 = 3791^2 + 2085^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4679725 + ... + 4679728.

Almost surely, 2^18718906 is an apocalyptic number.

18718906 is a deficient number, since it is larger than the sum of its proper divisors (9359456).

18718906 is an equidigital number, since it uses as much as digits as its factorization.

18718906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9359455.

The product of its (nonzero) digits is 24192, while the sum is 40.

The square root of 18718906 is about 4326.5351032899. The cubic root of 18718906 is about 265.5177063508.

The spelling of 18718906 in words is "eighteen million, seven hundred eighteen thousand, nine hundred six".