640386566406 has 32 divisors (see below), whose sum is σ = 1461542918880. Its totient is φ = 207692939808.

The previous prime is 640386566399. The next prime is 640386566419. The reversal of 640386566406 is 604665683046.

It is a happy number.

640386566406 is a `hidden beast` number, since 6 + 4 + 0 + 38 + 6 + 566 + 40 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 160254901 + ... + 160258896.

It is an arithmetic number, because the mean of its divisors is an integer number (45673216215).

Almost surely, 2^640386566406 is an apocalyptic number.

640386566406 is an abundant number, since it is smaller than the sum of its proper divisors (821156352474).

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

640386566406 is a wasteful number, since it uses less digits than its factorization.

640386566406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320513845 (or 320513839 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 54.

The spelling of 640386566406 in words is "six hundred forty billion, three hundred eighty-six million, five hundred sixty-six thousand, four hundred six".