21450852978912 has 384 divisors, whose sum is σ = 75727972454400. Its totient is φ = 5770619739648.

The previous prime is 21450852978883. The next prime is 21450852978923. The reversal of 21450852978912 is 21987925805412.

21450852978912 is a `hidden beast` number, since 2 + 1 + 4 + 508 + 52 + 9 + 78 + 9 + 1 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a self number, because there is not a number n which added to its sum of digits gives 21450852978912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18158043 + ... + 19303269.

It is an arithmetic number, because the mean of its divisors is an integer number (197208261600).

Almost surely, 2^{21450852978912} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21450852978912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37863986227200).

21450852978912 is an abundant number, since it is smaller than the sum of its proper divisors (54277119475488).

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

21450852978912 is a wasteful number, since it uses less digits than its factorization.

21450852978912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145435 (or 1145421 counting only the distinct ones).

The product of its (nonzero) digits is 29030400, while the sum is 63.

The spelling of 21450852978912 in words is "twenty-one trillion, four hundred fifty billion, eight hundred fifty-two million, nine hundred seventy-eight thousand, nine hundred twelve".