725813991 has 24 divisors (see below), whose sum is σ = 1199352960. Its totient is φ = 414341136.

The previous prime is 725813981. The next prime is 725813993. The reversal of 725813991 is 199318527.

725813991 is a `hidden beast` number, since 7 + 258 + 1 + 399 + 1 = 666.

725813991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 725813991 - 2¹⁴ = 725797607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (725813993) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 65620 + ... + 75878.

It is an arithmetic number, because the mean of its divisors is an integer number (49973040).

Almost surely, 2^725813991 is an apocalyptic number.

725813991 is a deficient number, since it is larger than the sum of its proper divisors (473538969).

725813991 is a wasteful number, since it uses less digits than its factorization.

725813991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11395 (or 11392 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 725813991 is about 26940.9352287555. The cubic root of 725813991 is about 898.6869705096.

The spelling of 725813991 in words is "seven hundred twenty-five million, eight hundred thirteen thousand, nine hundred ninety-one".