640155640020 has 96 divisors (see below), whose sum is σ = 1957503179520. Its totient is φ = 155357368320.

The previous prime is 640155639983. The next prime is 640155640021. The reversal of 640155640020 is 20046551046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640155640021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5724285 + ... + 5835044.

It is an arithmetic number, because the mean of its divisors is an integer number (20390658120).

Almost surely, 2^640155640020 is an apocalyptic number.

640155640020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640155640020 is an abundant number, since it is smaller than the sum of its proper divisors (1317347539500).

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

640155640020 is a wasteful number, since it uses less digits than its factorization.

640155640020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11559425 (or 11559423 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

The spelling of 640155640020 in words is "six hundred forty billion, one hundred fifty-five million, six hundred forty thousand, twenty".