21264223 has 2 divisors, whose sum is σ = 21264224. Its totient is φ = 21264222.

The previous prime is 21264209. The next prime is 21264239. The reversal of 21264223 is 32246212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21264223 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21264194 and 21264203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21264203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10632111 + 10632112.

It is an arithmetic number, because the mean of its divisors is an integer number (10632112).

Almost surely, 2^21264223 is an apocalyptic number.

21264223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21264223 is an equidigital number, since it uses as much as digits as its factorization.

21264223 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1152, while the sum is 22.

The square root of 21264223 is about 4611.3146715443. The cubic root of 21264223 is about 277.0446955728.

The spelling of 21264223 in words is "twenty-one million, two hundred sixty-four thousand, two hundred twenty-three".