725521 has 4 divisors (see below), whose sum is σ = 727552. Its totient is φ = 723492.

The previous prime is 725519. The next prime is 725531. The reversal of 725521 is 125527.

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.

It is a cyclic number.

It is not a de Polignac number, because 725521 - 2¹ = 725519 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 725492 and 725501.

It is not an unprimeable number, because it can be changed into a prime (725531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 321 + ... + 1246.

It is an arithmetic number, because the mean of its divisors is an integer number (181888).

2⁷²⁵⁵²¹ is an apocalyptic number.

It is an amenable number.

725521 is a deficient number, since it is larger than the sum of its proper divisors (2031).

725521 is a wasteful number, since it uses less digits than its factorization.

725521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2030.

The product of its digits is 700, while the sum is 22.

The square root of 725521 is about 851.7752050864. The cubic root of 725521 is about 89.8566029224.

The spelling of 725521 in words is "seven hundred twenty-five thousand, five hundred twenty-one".