21201102281 has 2 divisors, whose sum is σ = 21201102282. Its totient is φ = 21201102280.

The previous prime is 21201102277. The next prime is 21201102283. The reversal of 21201102281 is 18220110212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21056621881 + 144480400 = 145109^2 + 12020^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201102281 - 2² = 21201102277 is a prime.

It is a super-2 number, since 2×21201102281² (a number of 21 digits) contains 22 as substring.

Together with 21201102283, 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 (21201102283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600551140 + 10600551141.

It is an arithmetic number, because the mean of its divisors is an integer number (10600551141).

Almost surely, 2^21201102281 is an apocalyptic number.

It is an amenable number.

21201102281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201102281 is an equidigital number, since it uses as much as digits as its factorization.

21201102281 is an odious number, because the sum of its binary digits is odd.

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

Adding to 21201102281 its reverse (18220110212), we get a palindrome (39421212493).

The spelling of 21201102281 in words is "twenty-one billion, two hundred one million, one hundred two thousand, two hundred eighty-one".