640476 has 18 divisors (see below), whose sum is σ = 1619072. Its totient is φ = 213480.

The previous prime is 640463. The next prime is 640477. The reversal of 640476 is 674046.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640476.

It is not an unprimeable number, because it can be changed into a prime (640477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8860 + ... + 8931.

2⁶⁴⁰⁴⁷⁶ is an apocalyptic number.

It is an amenable number.

640476 is an abundant number, since it is smaller than the sum of its proper divisors (978596).

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

640476 is a wasteful number, since it uses less digits than its factorization.

640476 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17801 (or 17796 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 640476 is about 800.2974447042. The cubic root of 640476 is about 86.1987471174.

The spelling of 640476 in words is "six hundred forty thousand, four hundred seventy-six".