21402223 has 2 divisors, whose sum is σ = 21402224. Its totient is φ = 21402222.

The previous prime is 21402221. The next prime is 21402229. The reversal of 21402223 is 32220412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21402223 - 2¹ = 21402221 is a prime.

Together with 21402221, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21402197 and 21402206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21402221) 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, 10701111 + 10701112.

It is an arithmetic number, because the mean of its divisors is an integer number (10701112).

Almost surely, 2^21402223 is an apocalyptic number.

21402223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21402223 is an equidigital number, since it uses as much as digits as its factorization.

21402223 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21402223 is about 4626.2536679261. The cubic root of 21402223 is about 277.6427228925.

Adding to 21402223 its reverse (32220412), we get a palindrome (53622635).

The spelling of 21402223 in words is "twenty-one million, four hundred two thousand, two hundred twenty-three".