21866668516686 has 16 divisors (see below), whose sum is σ = 49980956609664. Its totient is φ = 6247619576184.

The previous prime is 21866668516661. The next prime is 21866668516703. The reversal of 21866668516686 is 68661586666812.

It is a super-2 number, since 2×21866668516686² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260317482300 + ... + 260317482383.

It is an arithmetic number, because the mean of its divisors is an integer number (3123809788104).

Almost surely, 2^{21866668516686} is an apocalyptic number.

21866668516686 is an abundant number, since it is smaller than the sum of its proper divisors (28114288092978).

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

21866668516686 is a wasteful number, since it uses less digits than its factorization.

21866668516686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520634964695.

The product of its digits is 1433272320, while the sum is 75.

The spelling of 21866668516686 in words is "twenty-one trillion, eight hundred sixty-six billion, six hundred sixty-eight million, five hundred sixteen thousand, six hundred eighty-six".