20928279 has 4 divisors (see below), whose sum is σ = 27904376. Its totient is φ = 13952184.

The previous prime is 20928251. The next prime is 20928283. The reversal of 20928279 is 97282902.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20928279 - 2⁵ = 20928247 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 (20928209) 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, 3488044 + ... + 3488049.

It is an arithmetic number, because the mean of its divisors is an integer number (6976094).

Almost surely, 2^20928279 is an apocalyptic number.

20928279 is a deficient number, since it is larger than the sum of its proper divisors (6976097).

20928279 is an equidigital number, since it uses as much as digits as its factorization.

20928279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6976096.

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 20928279 is about 4574.7435993725. The cubic root of 20928279 is about 275.5779755853.

The spelling of 20928279 in words is "twenty million, nine hundred twenty-eight thousand, two hundred seventy-nine".