1211621897 has 2 divisors, whose sum is σ = 1211621898. Its totient is φ = 1211621896.

The previous prime is 1211621893. The next prime is 1211621911. The reversal of 1211621897 is 7981261121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1130909641 + 80712256 = 33629^2 + 8984^2 .

It is an emirp because it is prime and its reverse (7981261121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1211621897 - 2² = 1211621893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1211621897.

It is not a weakly prime, because it can be changed into another prime (1211621893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605810948 + 605810949.

It is an arithmetic number, because the mean of its divisors is an integer number (605810949).

Almost surely, 2^1211621897 is an apocalyptic number.

It is an amenable number.

1211621897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211621897 is an equidigital number, since it uses as much as digits as its factorization.

1211621897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 38.

The square root of 1211621897 is about 34808.3595850192. The cubic root of 1211621897 is about 1066.0781390906.

The spelling of 1211621897 in words is "one billion, two hundred eleven million, six hundred twenty-one thousand, eight hundred ninety-seven".