20722705 has 4 divisors (see below), whose sum is σ = 24867252. Its totient is φ = 16578160.

The previous prime is 20722687. The next prime is 20722769. The reversal of 20722705 is 50722702.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2163841 + 18558864 = 1471^2 + 4308^2 .

It is not a de Polignac number, because 20722705 - 2⁷ = 20722577 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20722705.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2072266 + ... + 2072275.

It is an arithmetic number, because the mean of its divisors is an integer number (6216813).

Almost surely, 2^20722705 is an apocalyptic number.

It is an amenable number.

20722705 is a deficient number, since it is larger than the sum of its proper divisors (4144547).

20722705 is an equidigital number, since it uses as much as digits as its factorization.

20722705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4144546.

The product of its (nonzero) digits is 1960, while the sum is 25.

The square root of 20722705 is about 4552.2197881913. The cubic root of 20722705 is about 274.6726904752.

The spelling of 20722705 in words is "twenty million, seven hundred twenty-two thousand, seven hundred five".