21021110281 has 2 divisors, whose sum is σ = 21021110282. Its totient is φ = 21021110280.

The previous prime is 21021110239. The next prime is 21021110293. The reversal of 21021110281 is 18201112012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20746081225 + 275029056 = 144035^2 + 16584^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021110281 - 2¹⁵ = 21021077513 is a prime.

It is a super-2 number, since 2×21021110281² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21021110581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510555140 + 10510555141.

It is an arithmetic number, because the mean of its divisors is an integer number (10510555141).

Almost surely, 2^21021110281 is an apocalyptic number.

It is an amenable number.

21021110281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021110281 is an equidigital number, since it uses as much as digits as its factorization.

21021110281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21021110281 its reverse (18201112012), we get a palindrome (39222222293).

The spelling of 21021110281 in words is "twenty-one billion, twenty-one million, one hundred ten thousand, two hundred eighty-one".