20121220197 has 12 divisors (see below), whose sum is σ = 31299676044. Its totient is φ = 12382289280.

The previous prime is 20121220187. The next prime is 20121220241. The reversal of 20121220197 is 79102212102.

It can be written as a sum of positive squares in 2 ways, for example, as 10750786596 + 9370433601 = 103686^2 + 96801^2 .

It is not a de Polignac number, because 20121220197 - 2⁴ = 20121220181 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121220197.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121220117) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 85988004 + ... + 85988237.

It is an arithmetic number, because the mean of its divisors is an integer number (2608306337).

Almost surely, 2^20121220197 is an apocalyptic number.

It is an amenable number.

20121220197 is a deficient number, since it is larger than the sum of its proper divisors (11178455847).

20121220197 is a wasteful number, since it uses less digits than its factorization.

20121220197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171976260 (or 171976257 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

Adding to 20121220197 its reverse (79102212102), we get a palindrome (99223432299).

The spelling of 20121220197 in words is "twenty billion, one hundred twenty-one million, two hundred twenty thousand, one hundred ninety-seven".