21311132121 has 24 divisors (see below), whose sum is σ = 31761859584. Its totient is φ = 13761757440.

The previous prime is 21311132077. The next prime is 21311132137. The reversal of 21311132121 is 12123111312.

21311132121 is a `hidden beast` number, since 213 + 111 + 321 + 21 = 666.

It is not a de Polignac number, because 21311132121 - 2¹¹ = 21311130073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21311132094 and 21311132103.

It is not an unprimeable number, because it can be changed into a prime (21311032121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 218665 + ... + 300726.

It is an arithmetic number, because the mean of its divisors is an integer number (1323410816).

Almost surely, 2^21311132121 is an apocalyptic number.

It is an amenable number.

21311132121 is a deficient number, since it is larger than the sum of its proper divisors (10450727463).

21311132121 is a wasteful number, since it uses less digits than its factorization.

21311132121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 519541 (or 519538 counting only the distinct ones).

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

Adding to 21311132121 its reverse (12123111312), we get a palindrome (33434243433).

The spelling of 21311132121 in words is "twenty-one billion, three hundred eleven million, one hundred thirty-two thousand, one hundred twenty-one".