21984385940001 has 81 divisors (see below), whose sum is σ = 33305863157931. Its totient is φ = 13973528260224.

The previous prime is 21984385939993. The next prime is 21984385940053. The reversal of 21984385940001 is 10004958348912.

It is a happy number.

The square root of 21984385940001 is 4688751.

It is a perfect power (a square), and thus also a powerful number.

21984385940001 is a `hidden beast` number, since 2 + 1 + 9 + 8 + 43 + 8 + 594 + 0 + 0 + 0 + 1 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 297444798225 + 21686941141776 = 545385^2 + 4656924^2 .

It is not a de Polignac number, because 21984385940001 - 2³ = 21984385939993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21984385940001.

It is not an unprimeable number, because it can be changed into a prime (21984385940501) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 27583921735 + ... + 27583922531.

Almost surely, 2^{21984385940001} is an apocalyptic number.

21984385940001 is the 4688751-st square number.

21984385940001 is the 2344376-th centered octagonal number.

It is an amenable number.

21984385940001 is a deficient number, since it is larger than the sum of its proper divisors (11321477217930).

21984385940001 is an frugal number, since it uses more digits than its factorization.

21984385940001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1780 (or 890 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 54.

The spelling of 21984385940001 in words is "twenty-one trillion, nine hundred eighty-four billion, three hundred eighty-five million, nine hundred forty thousand, one".