721404071831 has 2 divisors, whose sum is σ = 721404071832. Its totient is φ = 721404071830.

The previous prime is 721404071813. The next prime is 721404071887. The reversal of 721404071831 is 138170404127.

Together with previous prime (721404071813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721404071831 is a prime.

It is a super-2 number, since 2×721404071831² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721404070831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360702035915 + 360702035916.

It is an arithmetic number, because the mean of its divisors is an integer number (360702035916).

Almost surely, 2^721404071831 is an apocalyptic number.

721404071831 is a deficient number, since it is larger than the sum of its proper divisors (1).

721404071831 is an equidigital number, since it uses as much as digits as its factorization.

721404071831 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 37632, while the sum is 38.

Adding to 721404071831 its reverse (138170404127), we get a palindrome (859574475958).

The spelling of 721404071831 in words is "seven hundred twenty-one billion, four hundred four million, seventy-one thousand, eight hundred thirty-one".