1211632181 has 2 divisors, whose sum is σ = 1211632182. Its totient is φ = 1211632180.

The previous prime is 1211632171. The next prime is 1211632183. The reversal of 1211632181 is 1812361121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 827080081 + 384552100 = 28759^2 + 19610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211632181 is a prime.

It is a super-2 number, since 2×1211632181² = 2936105084069633522, which contains 22 as substring.

Together with 1211632183, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211632181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211632183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605816090 + 605816091.

It is an arithmetic number, because the mean of its divisors is an integer number (605816091).

Almost surely, 2^1211632181 is an apocalyptic number.

It is an amenable number.

1211632181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211632181 is an equidigital number, since it uses as much as digits as its factorization.

1211632181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 26.

The square root of 1211632181 is about 34808.5073078407. The cubic root of 1211632181 is about 1066.0811553002.

The spelling of 1211632181 in words is "one billion, two hundred eleven million, six hundred thirty-two thousand, one hundred eighty-one".