725661990 has 40 divisors (see below), whose sum is σ = 1951226640. Its totient is φ = 193509648.

The previous prime is 725661971. The next prime is 725661997. The reversal of 725661990 is 99166527.

It is a happy number.

725661990 is a `hidden beast` number, since 7 + 25 + 6 + 619 + 9 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (725661997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 447130 + ... + 448749.

It is an arithmetic number, because the mean of its divisors is an integer number (48780666).

Almost surely, 2^725661990 is an apocalyptic number.

725661990 is an abundant number, since it is smaller than the sum of its proper divisors (1225564650).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

725661990 is a wasteful number, since it uses less digits than its factorization.

725661990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 895898 (or 895889 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 45.

The square root of 725661990 is about 26938.1140765273. The cubic root of 725661990 is about 898.6242313612.

The spelling of 725661990 in words is "seven hundred twenty-five million, six hundred sixty-one thousand, nine hundred ninety".