18921379 has 2 divisors, whose sum is σ = 18921380. Its totient is φ = 18921378.

The previous prime is 18921373. The next prime is 18921431. The reversal of 18921379 is 97312981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18921379 - 2⁵ = 18921347 is a prime.

It is not a weakly prime, because it can be changed into another prime (18921373) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9460689 + 9460690.

It is an arithmetic number, because the mean of its divisors is an integer number (9460690).

Almost surely, 2^18921379 is an apocalyptic number.

18921379 is a deficient number, since it is larger than the sum of its proper divisors (1).

18921379 is an equidigital number, since it uses as much as digits as its factorization.

18921379 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 40.

The square root of 18921379 is about 4349.8711475169. The cubic root of 18921379 is about 266.4715991826.

The spelling of 18921379 in words is "eighteen million, nine hundred twenty-one thousand, three hundred seventy-nine".