21866148399816 has 192 divisors, whose sum is σ = 67777698643200. Its totient is φ = 6238544707584.

The previous prime is 21866148399761. The next prime is 21866148399817. The reversal of 21866148399816 is 61899384166812.

21866148399816 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 61 + 483 + 9 + 9 + 81 + 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 not an unprimeable number, because it can be changed into a prime (21866148399817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1351172061 + ... + 1351188243.

It is an arithmetic number, because the mean of its divisors is an integer number (353008847100).

Almost surely, 2^{21866148399816} 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 21866148399816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33888849321600).

21866148399816 is an abundant number, since it is smaller than the sum of its proper divisors (45911550243384).

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

21866148399816 is a wasteful number, since it uses less digits than its factorization.

21866148399816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19868 (or 19861 counting only the distinct ones).

The product of its digits is 214990848, while the sum is 72.

The spelling of 21866148399816 in words is "twenty-one trillion, eight hundred sixty-six billion, one hundred forty-eight million, three hundred ninety-nine thousand, eight hundred sixteen".