661645896 has 32 divisors (see below), whose sum is σ = 1707475200. Its totient is φ = 213433920.

The previous prime is 661645879. The next prime is 661645909. The reversal of 661645896 is 698546166.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 443911 + ... + 445398.

It is an arithmetic number, because the mean of its divisors is an integer number (53358600).

Almost surely, 2^661645896 is an apocalyptic number.

It is an amenable number.

661645896 is an abundant number, since it is smaller than the sum of its proper divisors (1045829304).

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

661645896 is a wasteful number, since it uses less digits than its factorization.

661645896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 889349 (or 889345 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 51.

The square root of 661645896 is about 25722.4784186905. The cubic root of 661645896 is about 871.3819126654.

The spelling of 661645896 in words is "six hundred sixty-one million, six hundred forty-five thousand, eight hundred ninety-six".