20645722 has 4 divisors (see below), whose sum is σ = 30968586. Its totient is φ = 10322860.

The previous prime is 20645711. The next prime is 20645749. The reversal of 20645722 is 22754602.

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., 19105641 + 1540081 = 4371^2 + 1241^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5161429 + ... + 5161432.

Almost surely, 2^20645722 is an apocalyptic number.

20645722 is a deficient number, since it is larger than the sum of its proper divisors (10322864).

20645722 is a wasteful number, since it uses less digits than its factorization.

20645722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10322863.

The product of its (nonzero) digits is 6720, while the sum is 28.

The square root of 20645722 is about 4543.7563755113. The cubic root of 20645722 is about 274.3321402431.

The spelling of 20645722 in words is "twenty million, six hundred forty-five thousand, seven hundred twenty-two".