21311021223 has 12 divisors (see below), whose sum is σ = 30830172048. Its totient is φ = 14185384800.

The previous prime is 21311021219. The next prime is 21311021227. The reversal of 21311021223 is 32212011312.

It is an interprime number because it is at equal distance from previous prime (21311021219) and next prime (21311021227).

It is not a de Polignac number, because 21311021223 - 2² = 21311021219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311021196 and 21311021205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311021227) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1824078 + ... + 1835723.

It is an arithmetic number, because the mean of its divisors is an integer number (2569181004).

Almost surely, 2^21311021223 is an apocalyptic number.

21311021223 is a deficient number, since it is larger than the sum of its proper divisors (9519150825).

21311021223 is a wasteful number, since it uses less digits than its factorization.

21311021223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3660454 (or 3660451 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21311021223 its reverse (32212011312), we get a palindrome (53523032535).

The spelling of 21311021223 in words is "twenty-one billion, three hundred eleven million, twenty-one thousand, two hundred twenty-three".