18361919 has 4 divisors (see below), whose sum is σ = 18390360. Its totient is φ = 18333480.

The previous prime is 18361897. The next prime is 18361957. The reversal of 18361919 is 91916381.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18361919 - 2²⁴ = 1584703 is a prime.

It is a super-2 number, since 2×18361919² = 674320138725122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18361969) 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 in 3 ways as a sum of consecutive naturals, for example, 13229 + ... + 14550.

It is an arithmetic number, because the mean of its divisors is an integer number (4597590).

Almost surely, 2^18361919 is an apocalyptic number.

18361919 is a deficient number, since it is larger than the sum of its proper divisors (28441).

18361919 is an equidigital number, since it uses as much as digits as its factorization.

18361919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28440.

The product of its digits is 11664, while the sum is 38.

The square root of 18361919 is about 4285.0809793982. The cubic root of 18361919 is about 263.8189712033.

It can be divided in two parts, 183619 and 19, that multiplied together give a triangular number (3488761 = T₂₆₄₁).

The spelling of 18361919 in words is "eighteen million, three hundred sixty-one thousand, nine hundred nineteen".