725208721 has 4 divisors (see below), whose sum is σ = 725426100. Its totient is φ = 724991344.

The previous prime is 725208691. The next prime is 725208727. The reversal of 725208721 is 127802527.

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

It can be written as a sum of positive squares in 2 ways, for example, as 688485121 + 36723600 = 26239^2 + 6060^2 .

It is a cyclic number.

It is not a de Polignac number, because 725208721 - 2¹¹ = 725206673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (725208727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103606 + ... + 110383.

It is an arithmetic number, because the mean of its divisors is an integer number (181356525).

Almost surely, 2^725208721 is an apocalyptic number.

It is an amenable number.

725208721 is a deficient number, since it is larger than the sum of its proper divisors (217379).

725208721 is a wasteful number, since it uses less digits than its factorization.

725208721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217378.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 725208721 is about 26929.6996084249. The cubic root of 725208721 is about 898.4370903556.

The spelling of 725208721 in words is "seven hundred twenty-five million, two hundred eight thousand, seven hundred twenty-one".