18621389 has 4 divisors (see below), whose sum is σ = 18635520. Its totient is φ = 18607260.

The previous prime is 18621373. The next prime is 18621431. The reversal of 18621389 is 98312681.

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 18621389 - 2⁴ = 18621373 is a prime.

It is a super-2 number, since 2×18621389² = 693512256578642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18621319) 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, 4859 + ... + 7800.

It is an arithmetic number, because the mean of its divisors is an integer number (4658880).

Almost surely, 2^18621389 is an apocalyptic number.

It is an amenable number.

18621389 is a deficient number, since it is larger than the sum of its proper divisors (14131).

18621389 is a wasteful number, since it uses less digits than its factorization.

18621389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14130.

The product of its digits is 20736, while the sum is 38.

The square root of 18621389 is about 4315.2507459011. The cubic root of 18621389 is about 265.0558278012.

The spelling of 18621389 in words is "eighteen million, six hundred twenty-one thousand, three hundred eighty-nine".