20458921 has 10 divisors (see below), whose sum is σ = 23870122. Its totient is φ = 17534160.

The previous prime is 20458909. The next prime is 20458931. The reversal of 20458921 is 12985402.

It can be written as a sum of positive squares in only one way, i.e., 17347225 + 3111696 = 4165^2 + 1764^2 .

It is not a de Polignac number, because 20458921 - 2⁷ = 20458793 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 (20458931) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1860 + ... + 6661.

Almost surely, 2^20458921 is an apocalyptic number.

It is an amenable number.

20458921 is a deficient number, since it is larger than the sum of its proper divisors (3411201).

20458921 is an frugal number, since it uses more digits than its factorization.

20458921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8549 (or 8528 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 20458921 is about 4523.1538775505. The cubic root of 20458921 is about 273.5022531445.

The spelling of 20458921 in words is "twenty million, four hundred fifty-eight thousand, nine hundred twenty-one".