18717939 has 8 divisors (see below), whose sum is σ = 27730320. Its totient is φ = 12478608.

The previous prime is 18717931. The next prime is 18717947. The reversal of 18717939 is 93971781.

It is an interprime number because it is at equal distance from previous prime (18717931) and next prime (18717947).

It is not a de Polignac number, because 18717939 - 2³ = 18717931 is a prime.

It is a super-2 number, since 2×18717939² = 700722480815442, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18717894 and 18717903.

It is not an unprimeable number, because it can be changed into a prime (18717931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 346602 + ... + 346655.

It is an arithmetic number, because the mean of its divisors is an integer number (3466290).

Almost surely, 2^18717939 is an apocalyptic number.

18717939 is a deficient number, since it is larger than the sum of its proper divisors (9012381).

18717939 is an equidigital number, since it uses as much as digits as its factorization.

18717939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 693266 (or 693260 counting only the distinct ones).

The product of its digits is 95256, while the sum is 45.

The square root of 18717939 is about 4326.4233496042. The cubic root of 18717939 is about 265.5131341455.

The spelling of 18717939 in words is "eighteen million, seven hundred seventeen thousand, nine hundred thirty-nine".