21121221000012 has 24 divisors (see below), whose sum is σ = 56323256000256. Its totient is φ = 6034634571408.

The previous prime is 21121220999981. The next prime is 21121221000017. The reversal of 21121221000012 is 21000012212112.

It is a super-2 number, since 2×21121221000012² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121220999955 and 21121221000000.

It is not an unprimeable number, because it can be changed into a prime (21121221000017) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125721553488 + ... + 125721553655.

It is an arithmetic number, because the mean of its divisors is an integer number (2346802333344).

Almost surely, 2^{21121221000012} is an apocalyptic number.

It is an amenable number.

21121221000012 is an abundant number, since it is smaller than the sum of its proper divisors (35202035000244).

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

21121221000012 is a wasteful number, since it uses less digits than its factorization.

21121221000012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 251443107157 (or 251443107155 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21121221000012 its reverse (21000012212112), we get a palindrome (42121233212124).

The spelling of 21121221000012 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, twelve", and thus it is an aban number.