20640722 has 4 divisors (see below), whose sum is σ = 30961086. Its totient is φ = 10320360.

The previous prime is 20640713. The next prime is 20640733. The reversal of 20640722 is 22704602.

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

It can be written as a sum of positive squares in only one way, i.e., 20511841 + 128881 = 4529^2 + 359^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5160179 + ... + 5160182.

Almost surely, 2^20640722 is an apocalyptic number.

20640722 is a deficient number, since it is larger than the sum of its proper divisors (10320364).

20640722 is a wasteful number, since it uses less digits than its factorization.

20640722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10320363.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 20640722 is about 4543.2061366396. The cubic root of 20640722 is about 274.3099924515.

The spelling of 20640722 in words is "twenty million, six hundred forty thousand, seven hundred twenty-two".