21722056 has 16 divisors (see below), whose sum is σ = 43124940. Its totient is φ = 10222080.

The previous prime is 21722047. The next prime is 21722059. The reversal of 21722056 is 65022712.

It can be written as a sum of positive squares in 2 ways, for example, as 21436900 + 285156 = 4630^2 + 534^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21722056.

It is not an unprimeable number, because it can be changed into a prime (21722059) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 79725 + ... + 79996.

Almost surely, 2^21722056 is an apocalyptic number.

It is an amenable number.

21722056 is a deficient number, since it is larger than the sum of its proper divisors (21402884).

21722056 is a wasteful number, since it uses less digits than its factorization.

21722056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159744 (or 159740 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 21722056 is about 4660.6926523855. The cubic root of 21722056 is about 279.0189133430.

Adding to 21722056 its reverse (65022712), we get a palindrome (86744768).

The spelling of 21722056 in words is "twenty-one million, seven hundred twenty-two thousand, fifty-six".