1643699983968 has 1152 divisors, whose sum is σ = 6271437312000. Its totient is φ = 415529533440.

The previous prime is 1643699983943. The next prime is 1643699984029. The reversal of 1643699983968 is 8693899963461.

1643699983968 is a `hidden beast` number, since 1 + 6 + 4 + 369 + 99 + 83 + 96 + 8 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 723140080 + ... + 723142352.

It is an arithmetic number, because the mean of its divisors is an integer number (5443956000).

Almost surely, 2^{1643699983968} is an apocalyptic number.

1643699983968 is a gapful number since it is divisible by the number (18) 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 1643699983968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3135718656000).

1643699983968 is an abundant number, since it is smaller than the sum of its proper divisors (4627737328032).

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

1643699983968 is a wasteful number, since it uses less digits than its factorization.

1643699983968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2385 (or 2364 counting only the distinct ones).

The product of its digits is 3265173504, while the sum is 81.

The spelling of 1643699983968 in words is "one trillion, six hundred forty-three billion, six hundred ninety-nine million, nine hundred eighty-three thousand, nine hundred sixty-eight".