640306534 has 32 divisors (see below), whose sum is σ = 1141678080. Its totient is φ = 263603808.

The previous prime is 640306529. The next prime is 640306549. The reversal of 640306534 is 435603046.

It is a junction number, because it is equal to n+sod(n) for n = 640306496 and 640306505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33099 + ... + 48745.

It is an arithmetic number, because the mean of its divisors is an integer number (35677440).

Almost surely, 2^640306534 is an apocalyptic number.

640306534 is a deficient number, since it is larger than the sum of its proper divisors (501371546).

640306534 is a wasteful number, since it uses less digits than its factorization.

640306534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15772.

The product of its (nonzero) digits is 25920, while the sum is 31.

The square root of 640306534 is about 25304.2789662144. The cubic root of 640306534 is about 861.9114389451.

The spelling of 640306534 in words is "six hundred forty million, three hundred six thousand, five hundred thirty-four".