21666852929 has 2 divisors, whose sum is σ = 21666852930. Its totient is φ = 21666852928.

The previous prime is 21666852917. The next prime is 21666852931. The reversal of 21666852929 is 92925866612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21264930625 + 401922304 = 145825^2 + 20048^2 .

It is a cyclic number.

It is not a de Polignac number, because 21666852929 - 2¹⁶ = 21666787393 is a prime.

Together with 21666852931, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21666852979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10833426464 + 10833426465.

It is an arithmetic number, because the mean of its divisors is an integer number (10833426465).

Almost surely, 2^21666852929 is an apocalyptic number.

It is an amenable number.

21666852929 is a deficient number, since it is larger than the sum of its proper divisors (1).

21666852929 is an equidigital number, since it uses as much as digits as its factorization.

21666852929 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5598720, while the sum is 56.

The spelling of 21666852929 in words is "twenty-one billion, six hundred sixty-six million, eight hundred fifty-two thousand, nine hundred twenty-nine".