726643639 has 2 divisors, whose sum is σ = 726643640. Its totient is φ = 726643638.

The previous prime is 726643601. The next prime is 726643661. The reversal of 726643639 is 936346627.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 726643639 - 2²⁹ = 189772727 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (726643139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 363321819 + 363321820.

It is an arithmetic number, because the mean of its divisors is an integer number (363321820).

Almost surely, 2^726643639 is an apocalyptic number.

726643639 is a deficient number, since it is larger than the sum of its proper divisors (1).

726643639 is an equidigital number, since it uses as much as digits as its factorization.

726643639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 46.

The square root of 726643639 is about 26956.3283664523. The cubic root of 726643639 is about 899.0292574460.

It can be divided in two parts, 7266 and 43639, that added together give a palindrome (50905).

The spelling of 726643639 in words is "seven hundred twenty-six million, six hundred forty-three thousand, six hundred thirty-nine".