18945559 has 4 divisors (see below), whose sum is σ = 19348704. Its totient is φ = 18542416.

The previous prime is 18945551. The next prime is 18945581. The reversal of 18945559 is 95554981.

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 18945559 - 2³ = 18945551 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 (18945551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201502 + ... + 201595.

It is an arithmetic number, because the mean of its divisors is an integer number (4837176).

Almost surely, 2^18945559 is an apocalyptic number.

18945559 is a deficient number, since it is larger than the sum of its proper divisors (403145).

18945559 is an equidigital number, since it uses as much as digits as its factorization.

18945559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403144.

The product of its digits is 324000, while the sum is 46.

The square root of 18945559 is about 4352.6496527977. The cubic root of 18945559 is about 266.5850606195.

The spelling of 18945559 in words is "eighteen million, nine hundred forty-five thousand, five hundred fifty-nine".