20121220291 has 2 divisors, whose sum is σ = 20121220292. Its totient is φ = 20121220290.

The previous prime is 20121220279. The next prime is 20121220309. The reversal of 20121220291 is 19202212102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20121220291 - 2⁹ = 20121219779 is a prime.

It is not a weakly prime, because it can be changed into another prime (20121220241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060610145 + 10060610146.

It is an arithmetic number, because the mean of its divisors is an integer number (10060610146).

Almost surely, 2^20121220291 is an apocalyptic number.

20121220291 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121220291 is an equidigital number, since it uses as much as digits as its factorization.

20121220291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

Adding to 20121220291 its reverse (19202212102), we get a palindrome (39323432393).

The spelling of 20121220291 in words is "twenty billion, one hundred twenty-one million, two hundred twenty thousand, two hundred ninety-one".