21127686868 has 12 divisors (see below), whose sum is σ = 37972734772. Its totient is φ = 10278334080.

The previous prime is 21127686859. The next prime is 21127686869. The reversal of 21127686868 is 86868672112.

It can be written as a sum of positive squares in 2 ways, for example, as 7675862544 + 13451824324 = 87612^2 + 115982^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127686869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71377173 + ... + 71377468.

Almost surely, 2^21127686868 is an apocalyptic number.

It is an amenable number.

21127686868 is a deficient number, since it is larger than the sum of its proper divisors (16845047904).

21127686868 is a wasteful number, since it uses less digits than its factorization.

21127686868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142754682 (or 142754680 counting only the distinct ones).

The product of its digits is 3096576, while the sum is 55.

The spelling of 21127686868 in words is "twenty-one billion, one hundred twenty-seven million, six hundred eighty-six thousand, eight hundred sixty-eight".