20121221969 has 2 divisors, whose sum is σ = 20121221970. Its totient is φ = 20121221968.

The previous prime is 20121221927. The next prime is 20121221971. The reversal of 20121221969 is 96912212102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19248787600 + 872434369 = 138740^2 + 29537^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121221969 - 2²⁰ = 20120173393 is a prime.

It is a super-2 number, since 2×20121221969² (a number of 21 digits) contains 22 as substring.

Together with 20121221971, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20129221969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060610984 + 10060610985.

It is an arithmetic number, because the mean of its divisors is an integer number (10060610985).

Almost surely, 2^20121221969 is an apocalyptic number.

It is an amenable number.

20121221969 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121221969 is an equidigital number, since it uses as much as digits as its factorization.

20121221969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 35.

The spelling of 20121221969 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-one thousand, nine hundred sixty-nine".