640250406 has 20 divisors (see below), whose sum is σ = 1434635532. Its totient is φ = 213416748.

The previous prime is 640250357. The next prime is 640250407. The reversal of 640250406 is 604052046.

It is a happy number.

640250406 is a `hidden beast` number, since 6 + 4 + 0 + 250 + 406 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 640250406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640250407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1975920 + ... + 1976243.

Almost surely, 2^640250406 is an apocalyptic number.

640250406 is an abundant number, since it is smaller than the sum of its proper divisors (794385126).

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

640250406 is a wasteful number, since it uses less digits than its factorization.

640250406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3952177 (or 3952168 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 640250406 is about 25303.1698804715. The cubic root of 640250406 is about 861.8862537271.

The spelling of 640250406 in words is "six hundred forty million, two hundred fifty thousand, four hundred six".