18678981 has 8 divisors (see below), whose sum is σ = 24969024. Its totient is φ = 12420800.

The previous prime is 18678977. The next prime is 18679009. The reversal of 18678981 is 18987681.

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

It is a cyclic number.

It is not a de Polignac number, because 18678981 - 2² = 18678977 is a prime.

It is a super-2 number, since 2×18678981² = 697808662396722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18678981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18678931) 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, 6561 + ... + 8966.

It is an arithmetic number, because the mean of its divisors is an integer number (3121128).

Almost surely, 2^18678981 is an apocalyptic number.

It is an amenable number.

18678981 is a deficient number, since it is larger than the sum of its proper divisors (6290043).

18678981 is a wasteful number, since it uses less digits than its factorization.

18678981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15931.

The product of its digits is 193536, while the sum is 48.

The square root of 18678981 is about 4321.9186711460. The cubic root of 18678981 is about 265.3288003667.

The spelling of 18678981 in words is "eighteen million, six hundred seventy-eight thousand, nine hundred eighty-one".