722641921 has 2 divisors, whose sum is σ = 722641922. Its totient is φ = 722641920.

The previous prime is 722641897. The next prime is 722641939. The reversal of 722641921 is 129146227.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 666930625 + 55711296 = 25825^2 + 7464^2 .

It is a cyclic number.

It is not a de Polignac number, because 722641921 - 2⁵ = 722641889 is a prime.

It is a super-2 number, since 2×722641921² = 1044422691973140482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (722645921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 361320960 + 361320961.

It is an arithmetic number, because the mean of its divisors is an integer number (361320961).

Almost surely, 2^722641921 is an apocalyptic number.

It is an amenable number.

722641921 is a deficient number, since it is larger than the sum of its proper divisors (1).

722641921 is an equidigital number, since it uses as much as digits as its factorization.

722641921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 34.

The square root of 722641921 is about 26881.9999442006. Note that the first 4 decimals coincide. The cubic root of 722641921 is about 897.3758628028.

The spelling of 722641921 in words is "seven hundred twenty-two million, six hundred forty-one thousand, nine hundred twenty-one".