725540821 has 16 divisors (see below), whose sum is σ = 792000000. Its totient is φ = 662026176.

The previous prime is 725540801. The next prime is 725540831. The reversal of 725540821 is 128045527.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 725540821 - 2¹³ = 725532629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (725540801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 262555 + ... + 265303.

It is an arithmetic number, because the mean of its divisors is an integer number (49500000).

Almost surely, 2^725540821 is an apocalyptic number.

It is an amenable number.

725540821 is a deficient number, since it is larger than the sum of its proper divisors (66459179).

725540821 is a wasteful number, since it uses less digits than its factorization.

725540821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3276.

The product of its (nonzero) digits is 22400, while the sum is 34.

The square root of 725540821 is about 26935.8649573389. The cubic root of 725540821 is about 898.5742119941.

The spelling of 725540821 in words is "seven hundred twenty-five million, five hundred forty thousand, eight hundred twenty-one".