640802178 has 48 divisors (see below), whose sum is σ = 1486308096. Its totient is φ = 206705520.

The previous prime is 640802167. The next prime is 640802203. The reversal of 640802178 is 871208046.

640802178 is a `hidden beast` number, since 640 + 8 + 0 + 2 + 1 + 7 + 8 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6201 + ... + 36332.

It is an arithmetic number, because the mean of its divisors is an integer number (30964752).

Almost surely, 2^640802178 is an apocalyptic number.

640802178 is an abundant number, since it is smaller than the sum of its proper divisors (845505918).

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

640802178 is a wasteful number, since it uses less digits than its factorization.

640802178 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42581 (or 42569 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 640802178 is about 25314.0707512640. The cubic root of 640802178 is about 862.1337757112.

The spelling of 640802178 in words is "six hundred forty million, eight hundred two thousand, one hundred seventy-eight".