18038561 has 4 divisors (see below), whose sum is σ = 18051072. Its totient is φ = 18026052.

The previous prime is 18038557. The next prime is 18038567. The reversal of 18038561 is 16583081.

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 cyclic number.

It is not a de Polignac number, because 18038561 - 2² = 18038557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18038567) 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, 3761 + ... + 7086.

It is an arithmetic number, because the mean of its divisors is an integer number (4512768).

Almost surely, 2^18038561 is an apocalyptic number.

It is an amenable number.

18038561 is a deficient number, since it is larger than the sum of its proper divisors (12511).

18038561 is a wasteful number, since it uses less digits than its factorization.

18038561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12510.

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 18038561 is about 4247.1827132818. The cubic root of 18038561 is about 262.2611511424.

The spelling of 18038561 in words is "eighteen million, thirty-eight thousand, five hundred sixty-one".