6638402985984 has 672 divisors, whose sum is σ = 24360490312704. Its totient is φ = 1691650621440.

The previous prime is 6638402985983. The next prime is 6638402985989. The reversal of 6638402985984 is 4895892048366.

It is a happy number.

6638402985984 is a `hidden beast` number, since 6 + 6 + 3 + 8 + 4 + 0 + 29 + 8 + 598 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6638402985983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 300872937 + ... + 300894999.

It is an arithmetic number, because the mean of its divisors is an integer number (36250729632).

Almost surely, 2^{6638402985984} is an apocalyptic number.

6638402985984 is a gapful number since it is divisible by the number (64) 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 6638402985984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12180245156352).

6638402985984 is an abundant number, since it is smaller than the sum of its proper divisors (17722087326720).

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

6638402985984 is a wasteful number, since it uses less digits than its factorization.

6638402985984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22166 (or 22139 counting only the distinct ones).

The product of its (nonzero) digits is 716636160, while the sum is 72.

The spelling of 6638402985984 in words is "six trillion, six hundred thirty-eight billion, four hundred two million, nine hundred eighty-five thousand, nine hundred eighty-four".