21220223 has 2 divisors, whose sum is σ = 21220224. Its totient is φ = 21220222.

The previous prime is 21220219. The next prime is 21220231. The reversal of 21220223 is 32202212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21220223 - 2² = 21220219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21220198 and 21220207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610111 + 10610112.

It is an arithmetic number, because the mean of its divisors is an integer number (10610112).

Almost surely, 2^21220223 is an apocalyptic number.

21220223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220223 is an equidigital number, since it uses as much as digits as its factorization.

21220223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 14.

The square root of 21220223 is about 4606.5413272867. The cubic root of 21220223 is about 276.8534763573.

Adding to 21220223 its reverse (32202212), we get a palindrome (53422435).

The spelling of 21220223 in words is "twenty-one million, two hundred twenty thousand, two hundred twenty-three".