21866389364736 has 560 divisors, whose sum is σ = 78587054367360. Its totient is φ = 5918698045440.

The previous prime is 21866389364719. The next prime is 21866389364749. The reversal of 21866389364736 is 63746398366812.

21866389364736 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 63 + 8 + 93 + 6 + 473 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

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

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 88128531 + ... + 88376301.

It is an arithmetic number, because the mean of its divisors is an integer number (140334025656).

Almost surely, 2^{21866389364736} 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 21866389364736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39293527183680).

21866389364736 is an abundant number, since it is smaller than the sum of its proper divisors (56720665002624).

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

21866389364736 is an equidigital number, since it uses as much as digits as its factorization.

21866389364736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247835 (or 247802 counting only the distinct ones).

The product of its digits is 1128701952, while the sum is 72.

The spelling of 21866389364736 in words is "twenty-one trillion, eight hundred sixty-six billion, three hundred eighty-nine million, three hundred sixty-four thousand, seven hundred thirty-six".