721675261 has 2 divisors, whose sum is σ = 721675262. Its totient is φ = 721675260.

The previous prime is 721675259. The next prime is 721675363. The reversal of 721675261 is 162576127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 714546361 + 7128900 = 26731^2 + 2670^2 .

It is a cyclic number.

It is not a de Polignac number, because 721675261 - 2¹ = 721675259 is a prime.

Together with 721675259, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721675261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721675231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360837630 + 360837631.

It is an arithmetic number, because the mean of its divisors is an integer number (360837631).

Almost surely, 2^721675261 is an apocalyptic number.

It is an amenable number.

721675261 is a deficient number, since it is larger than the sum of its proper divisors (1).

721675261 is an equidigital number, since it uses as much as digits as its factorization.

721675261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35280, while the sum is 37.

The square root of 721675261 is about 26864.0142383822. The cubic root of 721675261 is about 896.9755518484.

The spelling of 721675261 in words is "seven hundred twenty-one million, six hundred seventy-five thousand, two hundred sixty-one".