721597 has 2 divisors, whose sum is σ = 721598. Its totient is φ = 721596.

The previous prime is 721577. The next prime is 721613. The reversal of 721597 is 795127.

721597 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 470596 + 251001 = 686^2 + 501^2 .

It is an emirp because it is prime and its reverse (795127) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360798 + 360799.

It is an arithmetic number, because the mean of its divisors is an integer number (360799).

2⁷²¹⁵⁹⁷ is an apocalyptic number.

It is an amenable number.

721597 is a deficient number, since it is larger than the sum of its proper divisors (1).

721597 is an equidigital number, since it uses as much as digits as its factorization.

721597 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4410, while the sum is 31.

The square root of 721597 is about 849.4686574559. The cubic root of 721597 is about 89.6943126950.

The spelling of 721597 in words is "seven hundred twenty-one thousand, five hundred ninety-seven".