21066312961 has 2 divisors, whose sum is σ = 21066312962. Its totient is φ = 21066312960.

The previous prime is 21066312941. The next prime is 21066312979. The reversal of 21066312961 is 16921366012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19707948225 + 1358364736 = 140385^2 + 36856^2 .

It is a cyclic number.

It is not a de Polignac number, because 21066312961 - 2⁵ = 21066312929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21066312961.

It is not a weakly prime, because it can be changed into another prime (21066312941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10533156480 + 10533156481.

It is an arithmetic number, because the mean of its divisors is an integer number (10533156481).

Almost surely, 2^21066312961 is an apocalyptic number.

It is an amenable number.

21066312961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21066312961 is an equidigital number, since it uses as much as digits as its factorization.

21066312961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 37.

Adding to 21066312961 its reverse (16921366012), we get a palindrome (37987678973).

The spelling of 21066312961 in words is "twenty-one billion, sixty-six million, three hundred twelve thousand, nine hundred sixty-one".