721588261 has 2 divisors, whose sum is σ = 721588262. Its totient is φ = 721588260.

The previous prime is 721588247. The next prime is 721588313. The reversal of 721588261 is 162885127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 415548225 + 306040036 = 20385^2 + 17494^2 .

It is a cyclic number.

It is not a de Polignac number, because 721588261 - 2⁵ = 721588229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721588211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360794130 + 360794131.

It is an arithmetic number, because the mean of its divisors is an integer number (360794131).

Almost surely, 2^721588261 is an apocalyptic number.

It is an amenable number.

721588261 is a deficient number, since it is larger than the sum of its proper divisors (1).

721588261 is an equidigital number, since it uses as much as digits as its factorization.

721588261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53760, while the sum is 40.

The square root of 721588261 is about 26862.3949230146. The cubic root of 721588261 is about 896.9395060841.

The spelling of 721588261 in words is "seven hundred twenty-one million, five hundred eighty-eight thousand, two hundred sixty-one".