725009221 has 4 divisors (see below), whose sum is σ = 725511712. Its totient is φ = 724506732.

The previous prime is 725009213. The next prime is 725009227. The reversal of 725009221 is 122900527.

725009221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122900527 = 103 ⋅1193209.

It is a cyclic number.

It is not a de Polignac number, because 725009221 - 2³ = 725009213 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 725009221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (725009227) 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, 249075 + ... + 251968.

It is an arithmetic number, because the mean of its divisors is an integer number (181377928).

Almost surely, 2^725009221 is an apocalyptic number.

It is an amenable number.

725009221 is a deficient number, since it is larger than the sum of its proper divisors (502491).

725009221 is a wasteful number, since it uses less digits than its factorization.

725009221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502490.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 725009221 is about 26925.9952647994. The cubic root of 725009221 is about 898.3546981501.

Adding to 725009221 its reverse (122900527), we get a palindrome (847909748).

The spelling of 725009221 in words is "seven hundred twenty-five million, nine thousand, two hundred twenty-one".