21123213211231 has 32 divisors (see below), whose sum is σ = 22448806272000. Its totient is φ = 19819844795520.

The previous prime is 21123213211229. The next prime is 21123213211271. The reversal of 21123213211231 is 13211231232112.

It is not a de Polignac number, because 21123213211231 - 2¹ = 21123213211229 is a prime.

It is a super-2 number, since 2×21123213211231² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21123213211196 and 21123213211205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123213211211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2093267496 + ... + 2093277586.

It is an arithmetic number, because the mean of its divisors is an integer number (701525196000).

Almost surely, 2^{21123213211231} is an apocalyptic number.

21123213211231 is a deficient number, since it is larger than the sum of its proper divisors (1325593060769).

21123213211231 is a wasteful number, since it uses less digits than its factorization.

21123213211231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12319.

The product of its digits is 864, while the sum is 25.

Adding to 21123213211231 its reverse (13211231232112), we get a palindrome (34334444443343).

The spelling of 21123213211231 in words is "twenty-one trillion, one hundred twenty-three billion, two hundred thirteen million, two hundred eleven thousand, two hundred thirty-one".