721233431 has 2 divisors, whose sum is σ = 721233432. Its totient is φ = 721233430.

The previous prime is 721233413. The next prime is 721233433. The reversal of 721233431 is 134332127.

Together with previous prime (721233413) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is an emirp because it is prime and its reverse (134332127) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721233431 is a prime.

It is a super-2 number, since 2×721233431² = 1040355323984063522, which contains 22 as substring.

Together with 721233433, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721233431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721233433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360616715 + 360616716.

It is an arithmetic number, because the mean of its divisors is an integer number (360616716).

Almost surely, 2^721233431 is an apocalyptic number.

721233431 is a deficient number, since it is larger than the sum of its proper divisors (1).

721233431 is an equidigital number, since it uses as much as digits as its factorization.

721233431 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 26.

The square root of 721233431 is about 26855.7895247933. The cubic root of 721233431 is about 896.7924632144.

Adding to 721233431 its reverse (134332127), we get a palindrome (855565558).

The spelling of 721233431 in words is "seven hundred twenty-one million, two hundred thirty-three thousand, four hundred thirty-one".