21123133 has 2 divisors, whose sum is σ = 21123134. Its totient is φ = 21123132.

The previous prime is 21123119. The next prime is 21123143. The reversal of 21123133 is 33132112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15539364 + 5583769 = 3942^2 + 2363^2 .

It is a cyclic number.

It is not a de Polignac number, because 21123133 - 2¹³ = 21114941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561566 + 10561567.

It is an arithmetic number, because the mean of its divisors is an integer number (10561567).

Almost surely, 2^21123133 is an apocalyptic number.

It is an amenable number.

21123133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123133 is an equidigital number, since it uses as much as digits as its factorization.

21123133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 16.

The square root of 21123133 is about 4595.9909704002. The cubic root of 21123133 is about 276.4305966787.

Adding to 21123133 its reverse (33132112), we get a palindrome (54255245).

The spelling of 21123133 in words is "twenty-one million, one hundred twenty-three thousand, one hundred thirty-three".