21041666689 has 2 divisors, whose sum is σ = 21041666690. Its totient is φ = 21041666688.

The previous prime is 21041666651. The next prime is 21041666693. The reversal of 21041666689 is 98666614012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12322776064 + 8718890625 = 111008^2 + 93375^2 .

It is a cyclic number.

It is not a de Polignac number, because 21041666689 - 2¹⁹ = 21041142401 is a prime.

It is not a weakly prime, because it can be changed into another prime (21041666629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10520833344 + 10520833345.

It is an arithmetic number, because the mean of its divisors is an integer number (10520833345).

Almost surely, 2^21041666689 is an apocalyptic number.

It is an amenable number.

21041666689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21041666689 is an equidigital number, since it uses as much as digits as its factorization.

21041666689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 746496, while the sum is 49.

The spelling of 21041666689 in words is "twenty-one billion, forty-one million, six hundred sixty-six thousand, six hundred eighty-nine".