21312123311 has 16 divisors (see below), whose sum is σ = 22680241920. Its totient is φ = 19982772480.

The previous prime is 21312123289. The next prime is 21312123337. The reversal of 21312123311 is 11332121312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21312123311 - 2¹⁴ = 21312106927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312123211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 456776 + ... + 501266.

It is an arithmetic number, because the mean of its divisors is an integer number (1417515120).

Almost surely, 2^21312123311 is an apocalyptic number.

21312123311 is a deficient number, since it is larger than the sum of its proper divisors (1368118609).

21312123311 is a wasteful number, since it uses less digits than its factorization.

21312123311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44926.

The product of its digits is 216, while the sum is 20.

Adding to 21312123311 its reverse (11332121312), we get a palindrome (32644244623).

The spelling of 21312123311 in words is "twenty-one billion, three hundred twelve million, one hundred twenty-three thousand, three hundred eleven".