661604316 has 12 divisors (see below), whose sum is σ = 1543743432. Its totient is φ = 220534768.

The previous prime is 661604303. The next prime is 661604323. The reversal of 661604316 is 613406166.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent 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 3 ways as a sum of consecutive naturals, for example, 27566835 + ... + 27566858.

It is an arithmetic number, because the mean of its divisors is an integer number (128645286).

Almost surely, 2^661604316 is an apocalyptic number.

It is an amenable number.

661604316 is an abundant number, since it is smaller than the sum of its proper divisors (882139116).

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

661604316 is a wasteful number, since it uses less digits than its factorization.

661604316 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55133700 (or 55133698 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 33.

The square root of 661604316 is about 25721.6701635022. The cubic root of 661604316 is about 871.3636587831.

The spelling of 661604316 in words is "six hundred sixty-one million, six hundred four thousand, three hundred sixteen".