722639 has 2 divisors, whose sum is σ = 722640. Its totient is φ = 722638.

The previous prime is 722633. The next prime is 722663. The reversal of 722639 is 936227.

It is a weak prime.

It is an emirp because it is prime and its reverse (936227) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-722639 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (722633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 361319 + 361320.

It is an arithmetic number, because the mean of its divisors is an integer number (361320).

2⁷²²⁶³⁹ is an apocalyptic number.

722639 is a deficient number, since it is larger than the sum of its proper divisors (1).

722639 is an equidigital number, since it uses as much as digits as its factorization.

722639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4536, while the sum is 29.

The square root of 722639 is about 850.0817607736. The cubic root of 722639 is about 89.7374653703.

The spelling of 722639 in words is "seven hundred twenty-two thousand, six hundred thirty-nine".