725607666 has 128 divisors (see below), whose sum is σ = 1958976000. Its totient is φ = 194648832.

The previous prime is 725607647. The next prime is 725607713. The reversal of 725607666 is 666706527.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 404700 + ... + 406488.

It is an arithmetic number, because the mean of its divisors is an integer number (15304500).

Almost surely, 2^725607666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 725607666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (979488000).

725607666 is an abundant number, since it is smaller than the sum of its proper divisors (1233368334).

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

725607666 is a wasteful number, since it uses less digits than its factorization.

725607666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1873 (or 1867 counting only the distinct ones).

The product of its (nonzero) digits is 635040, while the sum is 45.

The square root of 725607666 is about 26937.1057465348. The cubic root of 725607666 is about 898.6018067422.

The spelling of 725607666 in words is "seven hundred twenty-five million, six hundred seven thousand, six hundred sixty-six".