21226823 has 2 divisors, whose sum is σ = 21226824. Its totient is φ = 21226822.

The previous prime is 21226771. The next prime is 21226831. The reversal of 21226823 is 32862212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21226823 - 2⁶ = 21226759 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21226792 and 21226801.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21226853) 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, 10613411 + 10613412.

It is an arithmetic number, because the mean of its divisors is an integer number (10613412).

Almost surely, 2^21226823 is an apocalyptic number.

21226823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226823 is an equidigital number, since it uses as much as digits as its factorization.

21226823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 26.

The square root of 21226823 is about 4607.2576441957. The cubic root of 21226823 is about 276.8821760799.

The spelling of 21226823 in words is "twenty-one million, two hundred twenty-six thousand, eight hundred twenty-three".