640236784020 has 24 divisors (see below), whose sum is σ = 1792662995424. Its totient is φ = 170729809056.

The previous prime is 640236784001. The next prime is 640236784063. The reversal of 640236784020 is 20487632046.

It is a super-2 number, since 2×640236784020² (a number of 24 digits) contains 22 as substring.

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, 5335306474 + ... + 5335306593.

It is an arithmetic number, because the mean of its divisors is an integer number (74694291476).

Almost surely, 2^640236784020 is an apocalyptic number.

640236784020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640236784020 is an abundant number, since it is smaller than the sum of its proper divisors (1152426211404).

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

640236784020 is a wasteful number, since it uses less digits than its factorization.

640236784020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10670613079 (or 10670613077 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 42.

The spelling of 640236784020 in words is "six hundred forty billion, two hundred thirty-six million, seven hundred eighty-four thousand, twenty".