21000133423 has 2 divisors, whose sum is σ = 21000133424. Its totient is φ = 21000133422.

The previous prime is 21000133411. The next prime is 21000133499. The reversal of 21000133423 is 32433100012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21000133423 - 2⁵ = 21000133391 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000133423.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000133523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500066711 + 10500066712.

It is an arithmetic number, because the mean of its divisors is an integer number (10500066712).

Almost surely, 2^21000133423 is an apocalyptic number.

21000133423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000133423 is an equidigital number, since it uses as much as digits as its factorization.

21000133423 is an evil number, because the sum of its binary digits is even.

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

Adding to 21000133423 its reverse (32433100012), we get a palindrome (53433233435).

The spelling of 21000133423 in words is "twenty-one billion, one hundred thirty-three thousand, four hundred twenty-three".