640708167 has 8 divisors (see below), whose sum is σ = 931939200. Its totient is φ = 388307960.

The previous prime is 640708153. The next prime is 640708219. The reversal of 640708167 is 761807046.

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

It is a cyclic number.

It is not a de Polignac number, because 640708167 - 2²² = 636513863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640708067) 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, 9707667 + ... + 9707732.

It is an arithmetic number, because the mean of its divisors is an integer number (116492400).

Almost surely, 2^640708167 is an apocalyptic number.

640708167 is a deficient number, since it is larger than the sum of its proper divisors (291231033).

640708167 is a wasteful number, since it uses less digits than its factorization.

640708167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19415413.

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 640708167 is about 25312.2137909745. The cubic root of 640708167 is about 862.0916129216.

It can be divided in two parts, 640 and 708167, that added together give a palindrome (708807).

The spelling of 640708167 in words is "six hundred forty million, seven hundred eight thousand, one hundred sixty-seven".