640774 has 4 divisors (see below), whose sum is σ = 961164. Its totient is φ = 320386.

The previous prime is 640771. The next prime is 640777. The reversal of 640774 is 477046.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (640771) and next prime (640777).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160192 + ... + 160195.

It is an arithmetic number, because the mean of its divisors is an integer number (240291).

2⁶⁴⁰⁷⁷⁴ is an apocalyptic number.

640774 is a deficient number, since it is larger than the sum of its proper divisors (320390).

640774 is a wasteful number, since it uses less digits than its factorization.

640774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320389.

The product of its (nonzero) digits is 4704, while the sum is 28.

The square root of 640774 is about 800.4836038296. The cubic root of 640774 is about 86.2121138654.

The spelling of 640774 in words is "six hundred forty thousand, seven hundred seventy-four".