21101212133 has 2 divisors, whose sum is σ = 21101212134. Its totient is φ = 21101212132.

The previous prime is 21101212123. The next prime is 21101212157. The reversal of 21101212133 is 33121210112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21087977089 + 13235044 = 145217^2 + 3638^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101212133 - 2⁸ = 21101211877 is a prime.

It is a super-2 number, since 2×21101212133² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101212103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550606066 + 10550606067.

It is an arithmetic number, because the mean of its divisors is an integer number (10550606067).

Almost surely, 2^21101212133 is an apocalyptic number.

It is an amenable number.

21101212133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101212133 is an equidigital number, since it uses as much as digits as its factorization.

21101212133 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21101212133 its reverse (33121210112), we get a palindrome (54222422245).

The spelling of 21101212133 in words is "twenty-one billion, one hundred one million, two hundred twelve thousand, one hundred thirty-three".