20928405 has 16 divisors (see below), whose sum is σ = 35248320. Its totient is φ = 10574208.

The previous prime is 20928373. The next prime is 20928407. The reversal of 20928405 is 50482902.

It is not a de Polignac number, because 20928405 - 2⁵ = 20928373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20928407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36432 + ... + 37001.

It is an arithmetic number, because the mean of its divisors is an integer number (2203020).

Almost surely, 2^20928405 is an apocalyptic number.

It is an amenable number.

20928405 is a deficient number, since it is larger than the sum of its proper divisors (14319915).

20928405 is a wasteful number, since it uses less digits than its factorization.

20928405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73460.

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 20928405 is about 4574.7573706154. The cubic root of 20928405 is about 275.5785286289.

The spelling of 20928405 in words is "twenty million, nine hundred twenty-eight thousand, four hundred five".