21008023 has 2 divisors, whose sum is σ = 21008024. Its totient is φ = 21008022.

The previous prime is 21008021. The next prime is 21008027. The reversal of 21008023 is 32080012.

It is a happy number.

21008023 is nontrivially palindromic in base 12.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21008023 - 2¹ = 21008021 is a prime.

Together with 21008021, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21007988 and 21008006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21008021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10504011 + 10504012.

It is an arithmetic number, because the mean of its divisors is an integer number (10504012).

Almost surely, 2^21008023 is an apocalyptic number.

21008023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21008023 is an equidigital number, since it uses as much as digits as its factorization.

21008023 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21008023 is about 4583.4509924292. The cubic root of 21008023 is about 275.9275478451.

Adding to 21008023 its reverse (32080012), we get a palindrome (53088035).

The spelling of 21008023 in words is "twenty-one million, eight thousand, twenty-three".