640404089784 has 32 divisors (see below), whose sum is σ = 1778900250000. Its totient is φ = 213468029856.

The previous prime is 640404089777. The next prime is 640404089789. The reversal of 640404089784 is 487980404046.

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

It is a self number, because there is not a number n which added to its sum of digits gives 640404089784.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640404089789) 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, 1482416659 + ... + 1482417090.

Almost surely, 2^640404089784 is an apocalyptic number.

It is an amenable number.

640404089784 is an abundant number, since it is smaller than the sum of its proper divisors (1138496160216).

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

640404089784 is a wasteful number, since it uses less digits than its factorization.

640404089784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2964833764 (or 2964833754 counting only the distinct ones).

The product of its (nonzero) digits is 6193152, while the sum is 54.

The spelling of 640404089784 in words is "six hundred forty billion, four hundred four million, eighty-nine thousand, seven hundred eighty-four".