20121221010 has 128 divisors (see below), whose sum is σ = 53359388928. Its totient is φ = 4815360000.

The previous prime is 20121220981. The next prime is 20121221033. The reversal of 20121221010 is 1012212102.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 15231150 + ... + 15232470.

It is an arithmetic number, because the mean of its divisors is an integer number (416870226).

Almost surely, 2^20121221010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20121221010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26679694464).

20121221010 is an abundant number, since it is smaller than the sum of its proper divisors (33238167918).

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

20121221010 is a wasteful number, since it uses less digits than its factorization.

20121221010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1900.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 20121221010 its reverse (1012212102), we get a palindrome (21133433112).

It can be divided in two parts, 201212 and 21010, that added together give a palindrome (222222).

The spelling of 20121221010 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, ten".