21722773 has 4 divisors (see below), whose sum is σ = 21763468. Its totient is φ = 21682080.

The previous prime is 21722759. The next prime is 21722791. The reversal of 21722773 is 37722712.

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 10284849 + 11437924 = 3207^2 + 3382^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21722773 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 (21722873) 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, 19536 + ... + 20617.

It is an arithmetic number, because the mean of its divisors is an integer number (5440867).

Almost surely, 2^21722773 is an apocalyptic number.

It is an amenable number.

21722773 is a deficient number, since it is larger than the sum of its proper divisors (40695).

21722773 is an equidigital number, since it uses as much as digits as its factorization.

21722773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40694.

The product of its digits is 8232, while the sum is 31.

The square root of 21722773 is about 4660.7695716480. The cubic root of 21722773 is about 279.0219832543.

The spelling of 21722773 in words is "twenty-one million, seven hundred twenty-two thousand, seven hundred seventy-three".