20121221204 has 12 divisors (see below), whose sum is σ = 40242442464. Its totient is φ = 8623380504.

The previous prime is 20121221161. The next prime is 20121221249. The reversal of 20121221204 is 40212212102.

20121221204 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 359307494 + ... + 359307549.

It is an arithmetic number, because the mean of its divisors is an integer number (3353536872).

Almost surely, 2^20121221204 is an apocalyptic number.

It is an amenable number.

20121221204 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20121221204 is a wasteful number, since it uses less digits than its factorization.

20121221204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 718615054 (or 718615052 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 20121221204 its reverse (40212212102), we get a palindrome (60333433306).

The spelling of 20121221204 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, two hundred four".