18409557 has 4 divisors (see below), whose sum is σ = 24546080. Its totient is φ = 12273036.

The previous prime is 18409549. The next prime is 18409583. The reversal of 18409557 is 75590481.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18409557 - 2³ = 18409549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18409507) 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 in 3 ways as a sum of consecutive naturals, for example, 3068257 + ... + 3068262.

It is an arithmetic number, because the mean of its divisors is an integer number (6136520).

Almost surely, 2^18409557 is an apocalyptic number.

It is an amenable number.

18409557 is a deficient number, since it is larger than the sum of its proper divisors (6136523).

18409557 is an equidigital number, since it uses as much as digits as its factorization.

18409557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6136522.

The product of its (nonzero) digits is 50400, while the sum is 39.

The square root of 18409557 is about 4290.6359668469. The cubic root of 18409557 is about 264.0469240512.

The spelling of 18409557 in words is "eighteen million, four hundred nine thousand, five hundred fifty-seven".