21023312121 has 96 divisors (see below), whose sum is σ = 36084142848. Its totient is φ = 11548293120.

The previous prime is 21023312119. The next prime is 21023312131. The reversal of 21023312121 is 12121332012.

21023312121 is a `hidden beast` number, since 210 + 2 + 331 + 2 + 121 = 666.

It is not a de Polignac number, because 21023312121 - 2¹ = 21023312119 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21023312094 and 21023312103.

It is not an unprimeable number, because it can be changed into a prime (21023312131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 38433570 + ... + 38434116.

It is an arithmetic number, because the mean of its divisors is an integer number (375876488).

Almost surely, 2^21023312121 is an apocalyptic number.

21023312121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21023312121 is a deficient number, since it is larger than the sum of its proper divisors (15060830727).

21023312121 is a wasteful number, since it uses less digits than its factorization.

21023312121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831 (or 828 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21023312121 its reverse (12121332012), we get a palindrome (33144644133).

The spelling of 21023312121 in words is "twenty-one billion, twenty-three million, three hundred twelve thousand, one hundred twenty-one".