21123212133 has 24 divisors (see below), whose sum is σ = 29997501600. Its totient is φ = 13218507936.

The previous prime is 21123212101. The next prime is 21123212137. The reversal of 21123212133 is 33121232112.

It is not a de Polignac number, because 21123212133 - 2⁵ = 21123212101 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123212137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28578 + ... + 207516.

It is an arithmetic number, because the mean of its divisors is an integer number (1249895900).

Almost surely, 2^21123212133 is an apocalyptic number.

It is an amenable number.

21123212133 is a deficient number, since it is larger than the sum of its proper divisors (8874289467).

21123212133 is a wasteful number, since it uses less digits than its factorization.

21123212133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179089 (or 179070 counting only the distinct ones).

The product of its digits is 432, while the sum is 21.

Adding to 21123212133 its reverse (33121232112), we get a palindrome (54244444245).

The spelling of 21123212133 in words is "twenty-one billion, one hundred twenty-three million, two hundred twelve thousand, one hundred thirty-three".