726641561 has 8 divisors (see below), whose sum is σ = 736878600. Its totient is φ = 716476288.

The previous prime is 726641537. The next prime is 726641579. The reversal of 726641561 is 165146627.

It can be written as a sum of positive squares in 4 ways, for example, as 15625 + 726625936 = 125^2 + 26956^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-726641561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (726646561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2615 + ... + 38211.

It is an arithmetic number, because the mean of its divisors is an integer number (92109825).

Almost surely, 2^726641561 is an apocalyptic number.

It is an amenable number.

726641561 is a deficient number, since it is larger than the sum of its proper divisors (10237039).

726641561 is a wasteful number, since it uses less digits than its factorization.

726641561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35883.

The product of its digits is 60480, while the sum is 38.

The square root of 726641561 is about 26956.2898225998. The cubic root of 726641561 is about 899.0284004534.

The spelling of 726641561 in words is "seven hundred twenty-six million, six hundred forty-one thousand, five hundred sixty-one".