640585290 has 16 divisors (see below), whose sum is σ = 1537404768. Its totient is φ = 170822736.

The previous prime is 640585237. The next prime is 640585291. The reversal of 640585290 is 92585046.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640585291) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10676392 + ... + 10676451.

It is an arithmetic number, because the mean of its divisors is an integer number (96087798).

Almost surely, 2^640585290 is an apocalyptic number.

640585290 is an abundant number, since it is smaller than the sum of its proper divisors (896819478).

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

640585290 is a wasteful number, since it uses less digits than its factorization.

640585290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21352853.

The product of its (nonzero) digits is 86400, while the sum is 39.

The square root of 640585290 is about 25309.7864471433. The cubic root of 640585290 is about 862.0364978634.

The spelling of 640585290 in words is "six hundred forty million, five hundred eighty-five thousand, two hundred ninety".