18879919 has 2 divisors, whose sum is σ = 18879920. Its totient is φ = 18879918.

The previous prime is 18879907. The next prime is 18880007. The reversal of 18879919 is 91997881.

It is a weak prime.

It is an emirp because it is prime and its reverse (91997881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18879919 - 2¹⁵ = 18847151 is a prime.

It is a super-2 number, since 2×18879919² = 712902682893122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18879019) 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 as a sum of consecutive naturals, namely, 9439959 + 9439960.

It is an arithmetic number, because the mean of its divisors is an integer number (9439960).

Almost surely, 2^18879919 is an apocalyptic number.

18879919 is a deficient number, since it is larger than the sum of its proper divisors (1).

18879919 is an equidigital number, since it uses as much as digits as its factorization.

18879919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 326592, while the sum is 52.

The square root of 18879919 is about 4345.1028756521. The cubic root of 18879919 is about 266.2768284662.

It can be divided in two parts, 188799 and 19, that multiplied together give a triangular number (3587181 = T₂₆₇₈).

The spelling of 18879919 in words is "eighteen million, eight hundred seventy-nine thousand, nine hundred nineteen".