721225591 has 2 divisors, whose sum is σ = 721225592. Its totient is φ = 721225590.

The previous prime is 721225577. The next prime is 721225607. The reversal of 721225591 is 195522127.

It is a weak prime.

It is an emirp because it is prime and its reverse (195522127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721225591 - 2⁹ = 721225079 is a prime.

It is a super-2 number, since 2×721225591² = 1040332706226598562, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721225511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360612795 + 360612796.

It is an arithmetic number, because the mean of its divisors is an integer number (360612796).

Almost surely, 2^721225591 is an apocalyptic number.

721225591 is a deficient number, since it is larger than the sum of its proper divisors (1).

721225591 is an equidigital number, since it uses as much as digits as its factorization.

721225591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12600, while the sum is 34.

The square root of 721225591 is about 26855.6435595947. The cubic root of 721225591 is about 896.7892137448.

The spelling of 721225591 in words is "seven hundred twenty-one million, two hundred twenty-five thousand, five hundred ninety-one".