18649979 has 2 divisors, whose sum is σ = 18649980. Its totient is φ = 18649978.

The previous prime is 18649973. The next prime is 18650041. The reversal of 18649979 is 97994681.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18649979 - 2¹² = 18645883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18649979.

It is not a weakly prime, because it can be changed into another prime (18649973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9324989 + 9324990.

It is an arithmetic number, because the mean of its divisors is an integer number (9324990).

Almost surely, 2^18649979 is an apocalyptic number.

18649979 is a deficient number, since it is larger than the sum of its proper divisors (1).

18649979 is an equidigital number, since it uses as much as digits as its factorization.

18649979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 53.

The square root of 18649979 is about 4318.5621449737. The cubic root of 18649979 is about 265.1914079344.

The spelling of 18649979 in words is "eighteen million, six hundred forty-nine thousand, nine hundred seventy-nine".