21064643773 has 2 divisors, whose sum is σ = 21064643774. Its totient is φ = 21064643772.

The previous prime is 21064643767. The next prime is 21064643779. The reversal of 21064643773 is 37734646012.

It is a balanced prime because it is at equal distance from previous prime (21064643767) and next prime (21064643779).

It can be written as a sum of positive squares in only one way, i.e., 14375530404 + 6689113369 = 119898^2 + 81787^2 .

It is a cyclic number.

It is not a de Polignac number, because 21064643773 - 2⁵ = 21064643741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21064643779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10532321886 + 10532321887.

It is an arithmetic number, because the mean of its divisors is an integer number (10532321887).

Almost surely, 2^21064643773 is an apocalyptic number.

It is an amenable number.

21064643773 is a deficient number, since it is larger than the sum of its proper divisors (1).

21064643773 is an equidigital number, since it uses as much as digits as its factorization.

21064643773 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 508032, while the sum is 43.

The spelling of 21064643773 in words is "twenty-one billion, sixty-four million, six hundred forty-three thousand, seven hundred seventy-three".