18456621 has 4 divisors (see below), whose sum is σ = 24608832. Its totient is φ = 12304412.

The previous prime is 18456593. The next prime is 18456623. The reversal of 18456621 is 12665481.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12665481 = 3 ⋅4221827.

It is a cyclic number.

It is not a de Polignac number, because 18456621 - 2¹³ = 18448429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18456623) 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, 3076101 + ... + 3076106.

It is an arithmetic number, because the mean of its divisors is an integer number (6152208).

Almost surely, 2^18456621 is an apocalyptic number.

It is an amenable number.

18456621 is a deficient number, since it is larger than the sum of its proper divisors (6152211).

18456621 is an equidigital number, since it uses as much as digits as its factorization.

18456621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6152210.

The product of its digits is 11520, while the sum is 33.

The square root of 18456621 is about 4296.1169676814. The cubic root of 18456621 is about 264.2717444075.

The spelling of 18456621 in words is "eighteen million, four hundred fifty-six thousand, six hundred twenty-one".