18685979 has 8 divisors (see below), whose sum is σ = 20309520. Its totient is φ = 17089056.

The previous prime is 18685973. The next prime is 18685981. The reversal of 18685979 is 97958681.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18685979 is a prime.

It is a super-2 number, since 2×18685979² = 698331622376882, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18685979.

It is not an unprimeable number, because it can be changed into a prime (18685973) 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, 5177 + ... + 8010.

It is an arithmetic number, because the mean of its divisors is an integer number (2538690).

Almost surely, 2^18685979 is an apocalyptic number.

18685979 is a deficient number, since it is larger than the sum of its proper divisors (1623541).

18685979 is a wasteful number, since it uses less digits than its factorization.

18685979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13309.

The product of its digits is 1088640, while the sum is 53.

The square root of 18685979 is about 4322.7281894655. The cubic root of 18685979 is about 265.3619309948.

The spelling of 18685979 in words is "eighteen million, six hundred eighty-five thousand, nine hundred seventy-nine".