22605721 has 2 divisors, whose sum is σ = 22605722. Its totient is φ = 22605720.

The previous prime is 22605697. The next prime is 22605743. The reversal of 22605721 is 12750622.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11971600 + 10634121 = 3460^2 + 3261^2 .

It is a cyclic number.

It is not a de Polignac number, because 22605721 - 2⁵ = 22605689 is a prime.

It is a super-2 number, since 2×22605721² = 1022037243859682, which contains 22 as substring.

It is equal to p_1424932 and since 22605721 and 1424932 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (22606721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11302860 + 11302861.

It is an arithmetic number, because the mean of its divisors is an integer number (11302861).

Almost surely, 2^22605721 is an apocalyptic number.

It is an amenable number.

22605721 is a deficient number, since it is larger than the sum of its proper divisors (1).

22605721 is an equidigital number, since it uses as much as digits as its factorization.

22605721 is an odious number, because the sum of its binary digits is odd.

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

The square root of 22605721 is about 4754.5474022245. The cubic root of 22605721 is about 282.7522835747.

The spelling of 22605721 in words is "twenty-two million, six hundred five thousand, seven hundred twenty-one".