21012033281 has 2 divisors, whose sum is σ = 21012033282. Its totient is φ = 21012033280.

The previous prime is 21012033257. The next prime is 21012033283. The reversal of 21012033281 is 18233021012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16636872256 + 4375161025 = 128984^2 + 66145^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012033281 - 2¹⁰ = 21012032257 is a prime.

It is a super-2 number, since 2×21012033281² (a number of 21 digits) contains 22 as substring.

Together with 21012033283, 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 (21012033283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506016640 + 10506016641.

It is an arithmetic number, because the mean of its divisors is an integer number (10506016641).

Almost surely, 2^21012033281 is an apocalyptic number.

It is an amenable number.

21012033281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012033281 is an equidigital number, since it uses as much as digits as its factorization.

21012033281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 21012033281 its reverse (18233021012), we get a palindrome (39245054293).

The spelling of 21012033281 in words is "twenty-one billion, twelve million, thirty-three thousand, two hundred eighty-one".