21133423 has 2 divisors, whose sum is σ = 21133424. Its totient is φ = 21133422.

The previous prime is 21133403. The next prime is 21133429. The reversal of 21133423 is 32433112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21133423 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21133423.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21133429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10566711 + 10566712.

It is an arithmetic number, because the mean of its divisors is an integer number (10566712).

Almost surely, 2^21133423 is an apocalyptic number.

21133423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21133423 is an equidigital number, since it uses as much as digits as its factorization.

21133423 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 19.

The square root of 21133423 is about 4597.1102879961. The cubic root of 21133423 is about 276.4754765280.

Adding to 21133423 its reverse (32433112), we get a palindrome (53566535).

The spelling of 21133423 in words is "twenty-one million, one hundred thirty-three thousand, four hundred twenty-three".