640185168 has 80 divisors (see below), whose sum is σ = 1894628736. Its totient is φ = 182469120.

The previous prime is 640185157. The next prime is 640185181. The reversal of 640185168 is 861581046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 152830 + ... + 156962.

Almost surely, 2^640185168 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640185168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (947314368).

640185168 is an abundant number, since it is smaller than the sum of its proper divisors (1254443568).

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

640185168 is a wasteful number, since it uses less digits than its factorization.

640185168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4612 (or 4606 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 39.

The square root of 640185168 is about 25301.8807206105. The cubic root of 640185168 is about 861.8569789076.

The spelling of 640185168 in words is "six hundred forty million, one hundred eighty-five thousand, one hundred sixty-eight".