20125621 has 4 divisors (see below), whose sum is σ = 21000672. Its totient is φ = 19250572.

The previous prime is 20125613. The next prime is 20125627. The reversal of 20125621 is 12652102.

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 20125621 - 2³ = 20125613 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 (20125627) 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, 437491 + ... + 437536.

It is an arithmetic number, because the mean of its divisors is an integer number (5250168).

Almost surely, 2^20125621 is an apocalyptic number.

It is an amenable number.

20125621 is a deficient number, since it is larger than the sum of its proper divisors (875051).

20125621 is an equidigital number, since it uses as much as digits as its factorization.

20125621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 875050.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 20125621 is about 4486.1588246517. The cubic root of 20125621 is about 272.0088890189.

Adding to 20125621 its reverse (12652102), we get a palindrome (32777723).

The spelling of 20125621 in words is "twenty million, one hundred twenty-five thousand, six hundred twenty-one".