725615021 has 4 divisors (see below), whose sum is σ = 727093344. Its totient is φ = 724136700.

The previous prime is 725614987. The next prime is 725615027. The reversal of 725615021 is 120516527.

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 725615021 - 2⁶ = 725614957 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 (725615027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 738425 + ... + 739406.

It is an arithmetic number, because the mean of its divisors is an integer number (181773336).

Almost surely, 2^725615021 is an apocalyptic number.

It is an amenable number.

725615021 is a deficient number, since it is larger than the sum of its proper divisors (1478323).

725615021 is a wasteful number, since it uses less digits than its factorization.

725615021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1478322.

The product of its (nonzero) digits is 4200, while the sum is 29.

The square root of 725615021 is about 26937.2422679086. The cubic root of 725615021 is about 898.6048429073.

The spelling of 725615021 in words is "seven hundred twenty-five million, six hundred fifteen thousand, twenty-one".