1211998169 has 2 divisors, whose sum is σ = 1211998170. Its totient is φ = 1211998168.

The previous prime is 1211998147. The next prime is 1211998181. The reversal of 1211998169 is 9618991121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 796368400 + 415629769 = 28220^2 + 20387^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211998169 is a prime.

It is a super-2 number, since 2×1211998169² = 2937879123318705122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1211998069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605999084 + 605999085.

It is an arithmetic number, because the mean of its divisors is an integer number (605999085).

Almost surely, 2^1211998169 is an apocalyptic number.

It is an amenable number.

1211998169 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211998169 is an equidigital number, since it uses as much as digits as its factorization.

1211998169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 47.

The square root of 1211998169 is about 34813.7640739981. The cubic root of 1211998169 is about 1066.1884853511.

The spelling of 1211998169 in words is "one billion, two hundred eleven million, nine hundred ninety-eight thousand, one hundred sixty-nine".