721832261 has 2 divisors, whose sum is σ = 721832262. Its totient is φ = 721832260.

The previous prime is 721832233. The next prime is 721832263. The reversal of 721832261 is 162238127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 680949025 + 40883236 = 26095^2 + 6394^2 .

It is an emirp because it is prime and its reverse (162238127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721832261 - 2⁶ = 721832197 is a prime.

Together with 721832263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721832263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360916130 + 360916131.

It is an arithmetic number, because the mean of its divisors is an integer number (360916131).

Almost surely, 2^721832261 is an apocalyptic number.

It is an amenable number.

721832261 is a deficient number, since it is larger than the sum of its proper divisors (1).

721832261 is an equidigital number, since it uses as much as digits as its factorization.

721832261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 32.

The square root of 721832261 is about 26866.9362041897. The cubic root of 721832261 is about 897.0405926215.

The spelling of 721832261 in words is "seven hundred twenty-one million, eight hundred thirty-two thousand, two hundred sixty-one".