21010212281 has 2 divisors, whose sum is σ = 21010212282. Its totient is φ = 21010212280.

The previous prime is 21010212259. The next prime is 21010212283. The reversal of 21010212281 is 18221201012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16152122281 + 4858090000 = 127091^2 + 69700^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21010212281 is a prime.

It is a super-2 number, since 2×21010212281² (a number of 21 digits) contains 22 as substring.

Together with 21010212283, 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 (21010212283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505106140 + 10505106141.

It is an arithmetic number, because the mean of its divisors is an integer number (10505106141).

Almost surely, 2^21010212281 is an apocalyptic number.

It is an amenable number.

21010212281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010212281 is an equidigital number, since it uses as much as digits as its factorization.

21010212281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21010212281 its reverse (18221201012), we get a palindrome (39231413293).

The spelling of 21010212281 in words is "twenty-one billion, ten million, two hundred twelve thousand, two hundred eighty-one".