21666267613740 has 192 divisors, whose sum is σ = 67083738624000. Its totient is φ = 5196971028480.

The previous prime is 21666267613703. The next prime is 21666267613747. The reversal of 21666267613740 is 4731676266612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21666267613747) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 27315261 + ... + 28097259.

It is an arithmetic number, because the mean of its divisors is an integer number (349394472000).

Almost surely, 2^{21666267613740} is an apocalyptic number.

21666267613740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21666267613740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33541869312000).

21666267613740 is an abundant number, since it is smaller than the sum of its proper divisors (45417471010260).

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

21666267613740 is a wasteful number, since it uses less digits than its factorization.

21666267613740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783232 (or 783230 counting only the distinct ones).

The product of its (nonzero) digits is 18289152, while the sum is 57.

The spelling of 21666267613740 in words is "twenty-one trillion, six hundred sixty-six billion, two hundred sixty-seven million, six hundred thirteen thousand, seven hundred forty".