18679981 has 8 divisors (see below), whose sum is σ = 18914400. Its totient is φ = 18447312.

The previous prime is 18679967. The next prime is 18679987. The reversal of 18679981 is 18997681.

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-18679981 is a prime.

It is a super-2 number, since 2×18679981² = 697883380320722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18679987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41946 + ... + 42388.

It is an arithmetic number, because the mean of its divisors is an integer number (2364300).

Almost surely, 2^18679981 is an apocalyptic number.

It is an amenable number.

18679981 is a deficient number, since it is larger than the sum of its proper divisors (234419).

18679981 is a wasteful number, since it uses less digits than its factorization.

18679981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875.

The product of its digits is 217728, while the sum is 49.

The square root of 18679981 is about 4322.0343589564. The cubic root of 18679981 is about 265.3335351729. Note that the first 3 decimals are identical.

The spelling of 18679981 in words is "eighteen million, six hundred seventy-nine thousand, nine hundred eighty-one".