18889979 has 2 divisors, whose sum is σ = 18889980. Its totient is φ = 18889978.

The previous prime is 18889973. The next prime is 18889993. The reversal of 18889979 is 97998881.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18889979 - 2¹² = 18885883 is a prime.

It is not a weakly prime, because it can be changed into another prime (18889973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9444989 + 9444990.

It is an arithmetic number, because the mean of its divisors is an integer number (9444990).

Almost surely, 2^18889979 is an apocalyptic number.

18889979 is a deficient number, since it is larger than the sum of its proper divisors (1).

18889979 is an equidigital number, since it uses as much as digits as its factorization.

18889979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2612736, while the sum is 59.

The square root of 18889979 is about 4346.2603465508. The cubic root of 18889979 is about 266.3241144962.

The spelling of 18889979 in words is "eighteen million, eight hundred eighty-nine thousand, nine hundred seventy-nine".