21221351233 has 2 divisors, whose sum is σ = 21221351234. Its totient is φ = 21221351232.

The previous prime is 21221351231. The next prime is 21221351251. The reversal of 21221351233 is 33215312212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19225763649 + 1995587584 = 138657^2 + 44672^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221351233 - 2¹ = 21221351231 is a prime.

Together with 21221351231, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21221351198 and 21221351207.

It is not a weakly prime, because it can be changed into another prime (21221351231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610675616 + 10610675617.

It is an arithmetic number, because the mean of its divisors is an integer number (10610675617).

Almost surely, 2^21221351233 is an apocalyptic number.

It is an amenable number.

21221351233 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221351233 is an equidigital number, since it uses as much as digits as its factorization.

21221351233 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 25.

Adding to 21221351233 its reverse (33215312212), we get a palindrome (54436663445).

The spelling of 21221351233 in words is "twenty-one billion, two hundred twenty-one million, three hundred fifty-one thousand, two hundred thirty-three".