20121201221 has 4 divisors (see below), whose sum is σ = 21950401344. Its totient is φ = 18292001100.

The previous prime is 20121201209. The next prime is 20121201223. The reversal of 20121201221 is 12210212102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20121201221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20121201196 and 20121201205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121201223) 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, 914600045 + ... + 914600066.

It is an arithmetic number, because the mean of its divisors is an integer number (5487600336).

Almost surely, 2^20121201221 is an apocalyptic number.

It is an amenable number.

20121201221 is a deficient number, since it is larger than the sum of its proper divisors (1829200123).

20121201221 is a wasteful number, since it uses less digits than its factorization.

20121201221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1829200122.

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

Adding to 20121201221 its reverse (12210212102), we get a palindrome (32331413323).

The spelling of 20121201221 in words is "twenty billion, one hundred twenty-one million, two hundred one thousand, two hundred twenty-one".