21230123 has 2 divisors, whose sum is σ = 21230124. Its totient is φ = 21230122.

The previous prime is 21230047. The next prime is 21230129. The reversal of 21230123 is 32103212.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21230123 - 2⁸ = 21229867 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a junction number, because it is equal to n+sod(n) for n = 21230098 and 21230107.

It is not a weakly prime, because it can be changed into another prime (21230129) 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, 10615061 + 10615062.

It is an arithmetic number, because the mean of its divisors is an integer number (10615062).

Almost surely, 2^21230123 is an apocalyptic number.

21230123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21230123 is an equidigital number, since it uses as much as digits as its factorization.

21230123 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 14.

The square root of 21230123 is about 4607.6157608898. The cubic root of 21230123 is about 276.8965237103.

Adding to 21230123 its reverse (32103212), we get a palindrome (53333335).

The spelling of 21230123 in words is "twenty-one million, two hundred thirty thousand, one hundred twenty-three".