20402879 has 4 divisors (see below), whose sum is σ = 23317584. Its totient is φ = 17488176.

The previous prime is 20402861. The next prime is 20402887. The reversal of 20402879 is 97820402.

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

It is a cyclic number.

It is not a de Polignac number, because 20402879 - 2⁸ = 20402623 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 (20402579) 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, 1457342 + ... + 1457355.

It is an arithmetic number, because the mean of its divisors is an integer number (5829396).

Almost surely, 2^20402879 is an apocalyptic number.

20402879 is a deficient number, since it is larger than the sum of its proper divisors (2914705).

20402879 is an equidigital number, since it uses as much as digits as its factorization.

20402879 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2914704.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 20402879 is about 4516.9546156675. The cubic root of 20402879 is about 273.2522948668.

The spelling of 20402879 in words is "twenty million, four hundred two thousand, eight hundred seventy-nine".