21221020133 has 2 divisors, whose sum is σ = 21221020134. Its totient is φ = 21221020132.

The previous prime is 21221020061. The next prime is 21221020141. The reversal of 21221020133 is 33102012212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18198549604 + 3022470529 = 134902^2 + 54977^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221020133 - 2²² = 21216825829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221028133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610510066 + 10610510067.

It is an arithmetic number, because the mean of its divisors is an integer number (10610510067).

Almost surely, 2^21221020133 is an apocalyptic number.

It is an amenable number.

21221020133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221020133 is an equidigital number, since it uses as much as digits as its factorization.

21221020133 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21221020133 its reverse (33102012212), we get a palindrome (54323032345).

The spelling of 21221020133 in words is "twenty-one billion, two hundred twenty-one million, twenty thousand, one hundred thirty-three".