640178 has 16 divisors (see below), whose sum is σ = 1197504. Its totient is φ = 249360.

The previous prime is 640163. The next prime is 640193. The reversal of 640178 is 871046.

It is an interprime number because it is at equal distance from previous prime (640163) and next prime (640193).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1925 + ... + 2232.

It is an arithmetic number, because the mean of its divisors is an integer number (74844).

2⁶⁴⁰¹⁷⁸ is an apocalyptic number.

640178 is a deficient number, since it is larger than the sum of its proper divisors (557326).

640178 is a wasteful number, since it uses less digits than its factorization.

640178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4177.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 640178 is about 800.1112422657. Note that the first 3 decimals coincide. The cubic root of 640178 is about 86.1853762227.

It can be divided in two parts, 640 and 178, that added together give a palindrome (818).

The spelling of 640178 in words is "six hundred forty thousand, one hundred seventy-eight".