21203023 has 2 divisors, whose sum is σ = 21203024. Its totient is φ = 21203022.

The previous prime is 21203011. The next prime is 21203041. The reversal of 21203023 is 32030212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21203023 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21202994 and 21203012.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203003) 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, 10601511 + 10601512.

It is an arithmetic number, because the mean of its divisors is an integer number (10601512).

Almost surely, 2^21203023 is an apocalyptic number.

21203023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203023 is an equidigital number, since it uses as much as digits as its factorization.

21203023 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21203023 is about 4604.6740384092. The cubic root of 21203023 is about 276.7786551683.

Adding to 21203023 its reverse (32030212), we get a palindrome (53233235).

The spelling of 21203023 in words is "twenty-one million, two hundred three thousand, twenty-three".