1211199965 has 4 divisors (see below), whose sum is σ = 1453439964. Its totient is φ = 968959968.

The previous prime is 1211199953. The next prime is 1211199971. The reversal of 1211199965 is 5699911121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 468419449 + 742780516 = 21643^2 + 27254^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211199965 - 2¹⁰ = 1211198941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121119992 + ... + 121120001.

It is an arithmetic number, because the mean of its divisors is an integer number (363359991).

Almost surely, 2^1211199965 is an apocalyptic number.

It is an amenable number.

1211199965 is a deficient number, since it is larger than the sum of its proper divisors (242239999).

1211199965 is an equidigital number, since it uses as much as digits as its factorization.

1211199965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 242239998.

The product of its digits is 43740, while the sum is 44.

The square root of 1211199965 is about 34802.2982718096. The cubic root of 1211199965 is about 1065.9543753140.

The spelling of 1211199965 in words is "one billion, two hundred eleven million, one hundred ninety-nine thousand, nine hundred sixty-five".