726239561 has 4 divisors (see below), whose sum is σ = 726296772. Its totient is φ = 726182352.

The previous prime is 726239557. The next prime is 726239593. The reversal of 726239561 is 165932627.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 70879561 + 655360000 = 8419^2 + 25600^2 .

It is a cyclic number.

It is not a de Polignac number, because 726239561 - 2² = 726239557 is a prime.

It is a super-2 number, since 2×726239561² = 1054847799922945442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (726239531) 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, 86 + ... + 38111.

It is an arithmetic number, because the mean of its divisors is an integer number (181574193).

Almost surely, 2^726239561 is an apocalyptic number.

It is an amenable number.

726239561 is a deficient number, since it is larger than the sum of its proper divisors (57211).

726239561 is a wasteful number, since it uses less digits than its factorization.

726239561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57210.

The product of its digits is 136080, while the sum is 41.

The square root of 726239561 is about 26948.8322752582. The cubic root of 726239561 is about 898.8625800066.

The spelling of 726239561 in words is "seven hundred twenty-six million, two hundred thirty-nine thousand, five hundred sixty-one".