21891115984668 has 24 divisors (see below), whose sum is σ = 58376309292672. Its totient is φ = 6254604567024.

The previous prime is 21891115984663. The next prime is 21891115984681. The reversal of 21891115984668 is 86648951119812.

It is a super-3 number, since 3×21891115984668³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21891115984663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 130304261730 + ... + 130304261897.

It is an arithmetic number, because the mean of its divisors is an integer number (2432346220528).

Almost surely, 2^{21891115984668} is an apocalyptic number.

21891115984668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21891115984668 is an abundant number, since it is smaller than the sum of its proper divisors (36485193308004).

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

21891115984668 is a wasteful number, since it uses less digits than its factorization.

21891115984668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260608523641 (or 260608523639 counting only the distinct ones).

The product of its digits is 59719680, while the sum is 69.

The spelling of 21891115984668 in words is "twenty-one trillion, eight hundred ninety-one billion, one hundred fifteen million, nine hundred eighty-four thousand, six hundred sixty-eight".