21812023 has 2 divisors, whose sum is σ = 21812024. Its totient is φ = 21812022.

The previous prime is 21812017. The next prime is 21812033. The reversal of 21812023 is 32021812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21812023 - 2⁹ = 21811511 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21812033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906011 + 10906012.

It is an arithmetic number, because the mean of its divisors is an integer number (10906012).

Almost surely, 2^21812023 is an apocalyptic number.

21812023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21812023 is an equidigital number, since it uses as much as digits as its factorization.

21812023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 21812023 is about 4670.3343563390. The cubic root of 21812023 is about 279.4035902222.

Adding to 21812023 its reverse (32021812), we get a palindrome (53833835).

The spelling of 21812023 in words is "twenty-one million, eight hundred twelve thousand, twenty-three".