20121221000 has 64 divisors (see below), whose sum is σ = 47679840000. Its totient is φ = 7946577600.

The previous prime is 20121220981. The next prime is 20121221033. The reversal of 20121221000 is 12212102.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48350 + ... + 206349.

It is an arithmetic number, because the mean of its divisors is an integer number (744997500).

Almost surely, 2^20121221000 is an apocalyptic number.

20121221000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20121221000 is an abundant number, since it is smaller than the sum of its proper divisors (27558619000).

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

20121221000 is a wasteful number, since it uses less digits than its factorization.

20121221000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254799 (or 254785 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20121221000 its reverse (12212102), we get a palindrome (20133433102).

The spelling of 20121221000 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand".