721675657 has 2 divisors, whose sum is σ = 721675658. Its totient is φ = 721675656.

The previous prime is 721675631. The next prime is 721675673. The reversal of 721675657 is 756576127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 641912896 + 79762761 = 25336^2 + 8931^2 .

It is a cyclic number.

It is not a de Polignac number, because 721675657 - 2²⁷ = 587457929 is a prime.

It is not a weakly prime, because it can be changed into another prime (721675627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360837828 + 360837829.

It is an arithmetic number, because the mean of its divisors is an integer number (360837829).

Almost surely, 2^721675657 is an apocalyptic number.

It is an amenable number.

721675657 is a deficient number, since it is larger than the sum of its proper divisors (1).

721675657 is an equidigital number, since it uses as much as digits as its factorization.

721675657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 617400, while the sum is 46.

The square root of 721675657 is about 26864.0216088359. The cubic root of 721675657 is about 896.9757159122.

The spelling of 721675657 in words is "seven hundred twenty-one million, six hundred seventy-five thousand, six hundred fifty-seven".