18039553 has 4 divisors (see below), whose sum is σ = 20616640. Its totient is φ = 15462468.

The previous prime is 18039529. The next prime is 18039563. The reversal of 18039553 is 35593081.

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 a de Polignac number, because none of the positive numbers 2^k-18039553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18039503) 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, 1288533 + ... + 1288546.

It is an arithmetic number, because the mean of its divisors is an integer number (5154160).

Almost surely, 2^18039553 is an apocalyptic number.

It is an amenable number.

18039553 is a deficient number, since it is larger than the sum of its proper divisors (2577087).

18039553 is an equidigital number, since it uses as much as digits as its factorization.

18039553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2577086.

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 18039553 is about 4247.2994949732. The cubic root of 18039553 is about 262.2659585897.

The spelling of 18039553 in words is "eighteen million, thirty-nine thousand, five hundred fifty-three".