640185166 has 4 divisors (see below), whose sum is σ = 960277752. Its totient is φ = 320092582.

The previous prime is 640185157. The next prime is 640185181. The reversal of 640185166 is 661581046.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160046290 + ... + 160046293.

It is an arithmetic number, because the mean of its divisors is an integer number (240069438).

Almost surely, 2^640185166 is an apocalyptic number.

640185166 is a deficient number, since it is larger than the sum of its proper divisors (320092586).

640185166 is a wasteful number, since it uses less digits than its factorization.

640185166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320092585.

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 640185166 is about 25301.8806810877. The cubic root of 640185166 is about 861.8569780101.

The spelling of 640185166 in words is "six hundred forty million, one hundred eighty-five thousand, one hundred sixty-six".