721655370031231 has 2 divisors, whose sum is σ = 721655370031232. Its totient is φ = 721655370031230.

The previous prime is 721655370031177. The next prime is 721655370031237. The reversal of 721655370031231 is 132130073556127.

It is a strong prime.

It is an emirp because it is prime and its reverse (132130073556127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721655370031231 - 2¹⁷ = 721655369900159 is a prime.

It is a super-2 number, since 2×721655370031231² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721655370031237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360827685015615 + 360827685015616.

It is an arithmetic number, because the mean of its divisors is an integer number (360827685015616).

Almost surely, 2^{721655370031231} is an apocalyptic number.

721655370031231 is a deficient number, since it is larger than the sum of its proper divisors (1).

721655370031231 is an equidigital number, since it uses as much as digits as its factorization.

721655370031231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 793800, while the sum is 46.

The spelling of 721655370031231 in words is "seven hundred twenty-one trillion, six hundred fifty-five billion, three hundred seventy million, thirty-one thousand, two hundred thirty-one".