21121223 has 2 divisors, whose sum is σ = 21121224. Its totient is φ = 21121222.

The previous prime is 21121211. The next prime is 21121231. The reversal of 21121223 is 32212112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121223 - 2⁴ = 21121207 is a prime.

It is a super-2 number, since 2×21121223² = 892212122031458, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121198 and 21121207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560611 + 10560612.

It is an arithmetic number, because the mean of its divisors is an integer number (10560612).

Almost surely, 2^21121223 is an apocalyptic number.

21121223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121223 is an equidigital number, since it uses as much as digits as its factorization.

21121223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48, while the sum is 14.

The square root of 21121223 is about 4595.7831759125. The cubic root of 21121223 is about 276.4222646073.

Adding to 21121223 its reverse (32212112), we get a palindrome (53333335).

The spelling of 21121223 in words is "twenty-one million, one hundred twenty-one thousand, two hundred twenty-three".