21311123211 has 48 divisors (see below), whose sum is σ = 38256513984. Its totient is φ = 11151654912.

The previous prime is 21311123189. The next prime is 21311123219. The reversal of 21311123211 is 11232111312.

21311123211 is a `hidden beast` number, since 21 + 311 + 12 + 321 + 1 = 666.

It is not a de Polignac number, because 21311123211 - 2⁶ = 21311123147 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21311123219) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 229270 + ... + 308523.

It is an arithmetic number, because the mean of its divisors is an integer number (797010708).

Almost surely, 2^21311123211 is an apocalyptic number.

21311123211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21311123211 is a deficient number, since it is larger than the sum of its proper divisors (16945390773).

21311123211 is a wasteful number, since it uses less digits than its factorization.

21311123211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537860 (or 537857 counting only the distinct ones).

The product of its digits is 72, while the sum is 18.

Adding to 21311123211 its reverse (11232111312), we get a palindrome (32543234523).

The spelling of 21311123211 in words is "twenty-one billion, three hundred eleven million, one hundred twenty-three thousand, two hundred eleven".