21120031212 has 24 divisors (see below), whose sum is σ = 56320083456. Its totient is φ = 6034294608.

The previous prime is 21120031211. The next prime is 21120031217. The reversal of 21120031212 is 21213002112.

It is a junction number, because it is equal to n+sod(n) for n = 21120031191 and 21120031200.

It is not an unprimeable number, because it can be changed into a prime (21120031211) 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 7 ways as a sum of consecutive naturals, for example, 125714388 + ... + 125714555.

It is an arithmetic number, because the mean of its divisors is an integer number (2346670144).

Almost surely, 2^21120031212 is an apocalyptic number.

It is an amenable number.

21120031212 is an abundant number, since it is smaller than the sum of its proper divisors (35200052244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21120031212 is a wasteful number, since it uses less digits than its factorization.

21120031212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251428957 (or 251428955 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21120031212 its reverse (21213002112), we get a palindrome (42333033324).

The spelling of 21120031212 in words is "twenty-one billion, one hundred twenty million, thirty-one thousand, two hundred twelve".