21864963306816 has 896 divisors, whose sum is σ = 78719198822400. Its totient is φ = 5812815052800.

The previous prime is 21864963306787. The next prime is 21864963306833. The reversal of 21864963306816 is 61860336946812.

21864963306816 is a `hidden beast` number, since 2 + 1 + 86 + 496 + 3 + 3 + 0 + 68 + 1 + 6 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2947948740 + ... + 2947956156.

Almost surely, 2^{21864963306816} 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 21864963306816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39359599411200).

21864963306816 is an abundant number, since it is smaller than the sum of its proper divisors (56854235515584).

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

21864963306816 is a wasteful number, since it uses less digits than its factorization.

21864963306816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7692 (or 7676 counting only the distinct ones).

The product of its (nonzero) digits is 53747712, while the sum is 63.

The spelling of 21864963306816 in words is "twenty-one trillion, eight hundred sixty-four billion, nine hundred sixty-three million, three hundred six thousand, eight hundred sixteen".