21121220012 has 12 divisors (see below), whose sum is σ = 37482728976. Its totient is φ = 10411868880.

The previous prime is 21121220011. The next prime is 21121220017. The reversal of 21121220012 is 21002212112.

It is a super-2 number, since 2×21121220012² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121220011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37184963 + ... + 37185530.

It is an arithmetic number, because the mean of its divisors is an integer number (3123560748).

Almost surely, 2^21121220012 is an apocalyptic number.

It is an amenable number.

21121220012 is a deficient number, since it is larger than the sum of its proper divisors (16361508964).

21121220012 is a wasteful number, since it uses less digits than its factorization.

21121220012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74370568 (or 74370566 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21121220012 its reverse (21002212112), we get a palindrome (42123432124).

The spelling of 21121220012 in words is "twenty-one billion, one hundred twenty-one million, two hundred twenty thousand, twelve".