646640243044320 has 768 divisors, whose sum is σ = 2439713877737472. Its totient is φ = 140761776291840.

The previous prime is 646640243044283. The next prime is 646640243044321. The reversal of 646640243044320 is 23440342046646.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 646640243044320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646640243044321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 18529949112 + ... + 18529984008.

It is an arithmetic number, because the mean of its divisors is an integer number (3176710778304).

Almost surely, 2^{646640243044320} is an apocalyptic number.

646640243044320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646640243044320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1219856938868736).

646640243044320 is an abundant number, since it is smaller than the sum of its proper divisors (1793073634693152).

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

646640243044320 is a wasteful number, since it uses less digits than its factorization.

646640243044320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35983 (or 35975 counting only the distinct ones).

The product of its (nonzero) digits is 7962624, while the sum is 48.

The spelling of 646640243044320 in words is "six hundred forty-six trillion, six hundred forty billion, two hundred forty-three million, forty-four thousand, three hundred twenty".