18065621 has 4 divisors (see below), whose sum is σ = 20646432. Its totient is φ = 15484812.

The previous prime is 18065617. The next prime is 18065627. The reversal of 18065621 is 12656081.

It is a happy number.

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 18065621 - 2² = 18065617 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 (18065627) 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, 1290395 + ... + 1290408.

It is an arithmetic number, because the mean of its divisors is an integer number (5161608).

Almost surely, 2^18065621 is an apocalyptic number.

It is an amenable number.

18065621 is a deficient number, since it is larger than the sum of its proper divisors (2580811).

18065621 is an equidigital number, since it uses as much as digits as its factorization.

18065621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2580810.

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 18065621 is about 4250.3671606110. The cubic root of 18065621 is about 262.3922266576.

The spelling of 18065621 in words is "eighteen million, sixty-five thousand, six hundred twenty-one".