21866218686 has 48 divisors (see below), whose sum is σ = 54022432464. Its totient is φ = 6332297472.

The previous prime is 21866218679. The next prime is 21866218711. The reversal of 21866218686 is 68681266812.

21866218686 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 621 + 8 + 6 + 8 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2744416 + ... + 2752371.

It is an arithmetic number, because the mean of its divisors is an integer number (1125467343).

Almost surely, 2^21866218686 is an apocalyptic number.

21866218686 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21866218686 is an abundant number, since it is smaller than the sum of its proper divisors (32156213778).

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

21866218686 is a wasteful number, since it uses less digits than its factorization.

21866218686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5496825 (or 5496822 counting only the distinct ones).

The product of its digits is 2654208, while the sum is 54.

The spelling of 21866218686 in words is "twenty-one billion, eight hundred sixty-six million, two hundred eighteen thousand, six hundred eighty-six".