640394005620 has 24 divisors (see below), whose sum is σ = 1793103215904. Its totient is φ = 170771734816.

The previous prime is 640394005579. The next prime is 640394005637. The reversal of 640394005620 is 26500493046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5336616654 + ... + 5336616773.

It is an arithmetic number, because the mean of its divisors is an integer number (74712633996).

Almost surely, 2^640394005620 is an apocalyptic number.

640394005620 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640394005620 is an abundant number, since it is smaller than the sum of its proper divisors (1152709210284).

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

640394005620 is a wasteful number, since it uses less digits than its factorization.

640394005620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10673233439 (or 10673233437 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 39.

Adding to 640394005620 its reverse (26500493046), we get a palindrome (666894498666).

The spelling of 640394005620 in words is "six hundred forty billion, three hundred ninety-four million, five thousand, six hundred twenty".