21731007866 has 8 divisors (see below), whose sum is σ = 32617505844. Its totient is φ = 10858505920.

The previous prime is 21731007839. The next prime is 21731007917. The reversal of 21731007866 is 66870013712.

It can be written as a sum of positive squares in 2 ways, for example, as 20356155625 + 1374852241 = 142675^2 + 37079^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3495125 + ... + 3501336.

Almost surely, 2^21731007866 is an apocalyptic number.

21731007866 is a deficient number, since it is larger than the sum of its proper divisors (10886497978).

21731007866 is a wasteful number, since it uses less digits than its factorization.

21731007866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6998016.

The product of its (nonzero) digits is 84672, while the sum is 41.

The spelling of 21731007866 in words is "twenty-one billion, seven hundred thirty-one million, seven thousand, eight hundred sixty-six".