21121221223 has 2 divisors, whose sum is σ = 21121221224. Its totient is φ = 21121221222.

The previous prime is 21121221221. The next prime is 21121221257. The reversal of 21121221223 is 32212212112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21121221223 - 2¹ = 21121221221 is a prime.

It is a super-2 number, since 2×21121221223² (a number of 21 digits) contains 22 as substring.

Together with 21121221221, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21121221223.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121221221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560610611 + 10560610612.

It is an arithmetic number, because the mean of its divisors is an integer number (10560610612).

Almost surely, 2^21121221223 is an apocalyptic number.

21121221223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121221223 is an equidigital number, since it uses as much as digits as its factorization.

21121221223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 19.

Adding to 21121221223 its reverse (32212212112), we get a palindrome (53333433335).

The spelling of 21121221223 in words is "twenty-one billion, one hundred twenty-one million, two hundred twenty-one thousand, two hundred twenty-three".