726666631 has 4 divisors (see below), whose sum is σ = 727645392. Its totient is φ = 725687872.

The previous prime is 726666617. The next prime is 726666637. The reversal of 726666631 is 136666627.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 726666631 - 2⁹ = 726666119 is a prime.

It is a super-2 number, since 2×726666631² = 1056088785217780322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (726666637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 488266 + ... + 489751.

It is an arithmetic number, because the mean of its divisors is an integer number (181911348).

Almost surely, 2^726666631 is an apocalyptic number.

726666631 is a deficient number, since it is larger than the sum of its proper divisors (978761).

726666631 is an equidigital number, since it uses as much as digits as its factorization.

726666631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 978760.

The product of its digits is 326592, while the sum is 43.

The square root of 726666631 is about 26956.7548306542. The cubic root of 726666631 is about 899.0387395184.

It can be divided in two parts, 72666 and 6631, that added together give a palindrome (79297).

The spelling of 726666631 in words is "seven hundred twenty-six million, six hundred sixty-six thousand, six hundred thirty-one".