640157678 has 8 divisors (see below), whose sum is σ = 1016721072. Its totient is φ = 301250656.

The previous prime is 640157663. The next prime is 640157711. The reversal of 640157678 is 876751046.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9414050 + ... + 9414117.

It is an arithmetic number, because the mean of its divisors is an integer number (127090134).

Almost surely, 2^640157678 is an apocalyptic number.

640157678 is a deficient number, since it is larger than the sum of its proper divisors (376563394).

640157678 is a wasteful number, since it uses less digits than its factorization.

640157678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18828186.

The product of its (nonzero) digits is 282240, while the sum is 44.

The square root of 640157678 is about 25301.3374745289. The cubic root of 640157678 is about 861.8446424833.

The spelling of 640157678 in words is "six hundred forty million, one hundred fifty-seven thousand, six hundred seventy-eight".