21722837 has 2 divisors, whose sum is σ = 21722838. Its totient is φ = 21722836.

The previous prime is 21722801. The next prime is 21722851. The reversal of 21722837 is 73822712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21446161 + 276676 = 4631^2 + 526^2 .

It is a cyclic number.

It is not a de Polignac number, because 21722837 - 2¹⁰ = 21721813 is a prime.

It is a Chen prime.

It is equal to p_1372793 and since 21722837 and 1372793 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21722887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10861418 + 10861419.

It is an arithmetic number, because the mean of its divisors is an integer number (10861419).

Almost surely, 2^21722837 is an apocalyptic number.

It is an amenable number.

21722837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21722837 is an equidigital number, since it uses as much as digits as its factorization.

21722837 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9408, while the sum is 32.

The square root of 21722837 is about 4660.7764374619. The cubic root of 21722837 is about 279.0222572738.

The spelling of 21722837 in words is "twenty-one million, seven hundred twenty-two thousand, eight hundred thirty-seven".