21221210069 has 2 divisors, whose sum is σ = 21221210070. Its totient is φ = 21221210068.

The previous prime is 21221210033. The next prime is 21221210111. The reversal of 21221210069 is 96001212212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19338517969 + 1882692100 = 139063^2 + 43390^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221210069 is a prime.

It is a super-2 number, since 2×21221210069² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221210369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610605034 + 10610605035.

It is an arithmetic number, because the mean of its divisors is an integer number (10610605035).

Almost surely, 2^21221210069 is an apocalyptic number.

It is an amenable number.

21221210069 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221210069 is an equidigital number, since it uses as much as digits as its factorization.

21221210069 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The spelling of 21221210069 in words is "twenty-one billion, two hundred twenty-one million, two hundred ten thousand, sixty-nine".