21866666812 has 48 divisors (see below), whose sum is σ = 40303065600. Its totient is φ = 10360848960.

The previous prime is 21866666791. The next prime is 21866666821.

21866666812 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×21866666812² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21866666812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4442889 + ... + 4447807.

It is an arithmetic number, because the mean of its divisors is an integer number (839647200).

Almost surely, 2^21866666812 is an apocalyptic number.

It is an amenable number.

21866666812 is a deficient number, since it is larger than the sum of its proper divisors (18436398788).

21866666812 is a wasteful number, since it uses less digits than its factorization.

21866666812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5386 (or 5384 counting only the distinct ones).

The product of its digits is 1990656, while the sum is 52.

The spelling of 21866666812 in words is "twenty-one billion, eight hundred sixty-six million, six hundred sixty-six thousand, eight hundred twelve".