1971021964800 has 480 divisors, whose sum is σ = 7469248723200. Its totient is φ = 448828047360.

The previous prime is 1971021964783. The next prime is 1971021964801. The reversal of 1971021964800 is 84691201791.

It is a tau number, because it is divible by the number of its divisors (480).

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 1971021964800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1971021964801) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 72293571 + ... + 72320829.

It is an arithmetic number, because the mean of its divisors is an integer number (15560934840).

Almost surely, 2^{1971021964800} is an apocalyptic number.

1971021964800 is a gapful number since it is divisible by the number (10) 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 1971021964800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3734624361600).

1971021964800 is an abundant number, since it is smaller than the sum of its proper divisors (5498226758400).

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

1971021964800 is a wasteful number, since it uses less digits than its factorization.

1971021964800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27566 (or 27545 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 48.

The spelling of 1971021964800 in words is "one trillion, nine hundred seventy-one billion, twenty-one million, nine hundred sixty-four thousand, eight hundred".