18405979 has 4 divisors (see below), whose sum is σ = 18416160. Its totient is φ = 18395800.

The previous prime is 18405977. The next prime is 18405991. The reversal of 18405979 is 97950481.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 18405979 - 2¹ = 18405977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18405977) 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, 1564 + ... + 6265.

It is an arithmetic number, because the mean of its divisors is an integer number (4604040).

Almost surely, 2^18405979 is an apocalyptic number.

18405979 is a deficient number, since it is larger than the sum of its proper divisors (10181).

18405979 is an equidigital number, since it uses as much as digits as its factorization.

18405979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10180.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 18405979 is about 4290.2189920795. The cubic root of 18405979 is about 264.0298166124.

The spelling of 18405979 in words is "eighteen million, four hundred five thousand, nine hundred seventy-nine".