20718679 has 4 divisors (see below), whose sum is σ = 20727784. Its totient is φ = 20709576.

The previous prime is 20718661. The next prime is 20718689. The reversal of 20718679 is 97681702.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20718679 - 2⁹ = 20718167 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 (20718689) 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, 2209 + ... + 6805.

It is an arithmetic number, because the mean of its divisors is an integer number (5181946).

Almost surely, 2^20718679 is an apocalyptic number.

20718679 is a deficient number, since it is larger than the sum of its proper divisors (9105).

20718679 is an equidigital number, since it uses as much as digits as its factorization.

20718679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9104.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 20718679 is about 4551.7775648641. Note that the first 3 decimals coincide. The cubic root of 20718679 is about 274.6549015512.

The spelling of 20718679 in words is "twenty million, seven hundred eighteen thousand, six hundred seventy-nine".