726665531 has 4 divisors (see below), whose sum is σ = 726878832. Its totient is φ = 726452232.

The previous prime is 726665521. The next prime is 726665549. The reversal of 726665531 is 135566627.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-726665531 is a prime.

It is a super-2 number, since 2×726665531² = 1056085587887023922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (726665501) 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, 101456 + ... + 108381.

It is an arithmetic number, because the mean of its divisors is an integer number (181719708).

Almost surely, 2^726665531 is an apocalyptic number.

726665531 is a deficient number, since it is larger than the sum of its proper divisors (213301).

726665531 is a wasteful number, since it uses less digits than its factorization.

726665531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213300.

The product of its digits is 226800, while the sum is 41.

The square root of 726665531 is about 26956.7344275971. The cubic root of 726665531 is about 899.0382858747.

The spelling of 726665531 in words is "seven hundred twenty-six million, six hundred sixty-five thousand, five hundred thirty-one".