21311033121 has 32 divisors (see below), whose sum is σ = 36172281600. Its totient is φ = 12147321600.

The previous prime is 21311033113. The next prime is 21311033141. The reversal of 21311033121 is 12133011312.

21311033121 is a `hidden beast` number, since 2 + 1 + 311 + 0 + 331 + 21 = 666.

It is not a de Polignac number, because 21311033121 - 2³ = 21311033113 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21311033094 and 21311033103.

It is not an unprimeable number, because it can be changed into a prime (21311033141) 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, 64806 + ... + 216383.

It is an arithmetic number, because the mean of its divisors is an integer number (1130383800).

Almost surely, 2^21311033121 is an apocalyptic number.

21311033121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21311033121 is a deficient number, since it is larger than the sum of its proper divisors (14861248479).

21311033121 is a wasteful number, since it uses less digits than its factorization.

21311033121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281606 (or 281600 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21311033121 its reverse (12133011312), we get a palindrome (33444044433).

The spelling of 21311033121 in words is "twenty-one billion, three hundred eleven million, thirty-three thousand, one hundred twenty-one".