21186663168 has 288 divisors, whose sum is σ = 67391170560. Its totient is φ = 5833031680.

The previous prime is 21186663163. The next prime is 21186663181. The reversal of 21186663168 is 86136668112.

It is a Harshad number since it is a multiple of its sum of digits (48).

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 (21186663163) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4162321 + ... + 4167407.

It is an arithmetic number, because the mean of its divisors is an integer number (233997120).

Almost surely, 2^21186663168 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 21186663168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33695585280).

21186663168 is an abundant number, since it is smaller than the sum of its proper divisors (46204507392).

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

21186663168 is a wasteful number, since it uses less digits than its factorization.

21186663168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5163 (or 5149 counting only the distinct ones).

The product of its digits is 497664, while the sum is 48.

The spelling of 21186663168 in words is "twenty-one billion, one hundred eighty-six million, six hundred sixty-three thousand, one hundred sixty-eight".