640663167 has 8 divisors (see below), whose sum is σ = 858049024. Its totient is φ = 425193048.

The previous prime is 640663141. The next prime is 640663189. The reversal of 640663167 is 761366046.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640663167 - 2⁷ = 640663039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640663567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478153 + ... + 479490.

It is an arithmetic number, because the mean of its divisors is an integer number (107256128).

Almost surely, 2^640663167 is an apocalyptic number.

640663167 is a deficient number, since it is larger than the sum of its proper divisors (217385857).

640663167 is a wasteful number, since it uses less digits than its factorization.

640663167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957869.

The product of its (nonzero) digits is 108864, while the sum is 39.

The square root of 640663167 is about 25311.3248764264. The cubic root of 640663167 is about 862.0714295095.

The spelling of 640663167 in words is "six hundred forty million, six hundred sixty-three thousand, one hundred sixty-seven".