20121220212091 has 2 divisors, whose sum is σ = 20121220212092. Its totient is φ = 20121220212090.

The previous prime is 20121220212089. The next prime is 20121220212173. The reversal of 20121220212091 is 19021202212102.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20121220212091 - 2¹ = 20121220212089 is a prime.

Together with 20121220212089, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20121290212091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060610106045 + 10060610106046.

It is an arithmetic number, because the mean of its divisors is an integer number (10060610106046).

Almost surely, 2^{20121220212091} is an apocalyptic number.

20121220212091 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121220212091 is an equidigital number, since it uses as much as digits as its factorization.

20121220212091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

Adding to 20121220212091 its reverse (19021202212102), we get a palindrome (39142422424193).

The spelling of 20121220212091 in words is "twenty trillion, one hundred twenty-one billion, two hundred twenty million, two hundred twelve thousand, ninety-one".