20445921 has 24 divisors (see below), whose sum is σ = 30741984. Its totient is φ = 13083840.

The previous prime is 20445889. The next prime is 20445923. The reversal of 20445921 is 12954402.

20445921 is a `hidden beast` number, since 204 + 459 + 2 + 1 = 666.

It is not a de Polignac number, because 20445921 - 2⁵ = 20445889 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20445923) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24310 + ... + 25136.

It is an arithmetic number, because the mean of its divisors is an integer number (1280916).

Almost surely, 2^20445921 is an apocalyptic number.

It is an amenable number.

20445921 is a deficient number, since it is larger than the sum of its proper divisors (10296063).

20445921 is a wasteful number, since it uses less digits than its factorization.

20445921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 941 (or 938 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 20445921 is about 4521.7165988151. The cubic root of 20445921 is about 273.4443113035. Note that the first 3 decimals are identical.

It can be divided in two parts, 204459 and 21, that added together give a triangular number (204480 = T₆₃₉).

The spelling of 20445921 in words is "twenty million, four hundred forty-five thousand, nine hundred twenty-one".