1211209999919 has 4 divisors (see below), whose sum is σ = 1213837353960. Its totient is φ = 1208582645880.

The previous prime is 1211209999913. The next prime is 1211209999921. The reversal of 1211209999919 is 9199999021121.

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

It is a cyclic number.

It is not a de Polignac number, because 1211209999919 - 2⁴ = 1211209999903 is a prime.

It is a super-2 number, since 2×1211209999919² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211209999913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1313676329 + ... + 1313677250.

It is an arithmetic number, because the mean of its divisors is an integer number (303459338490).

Almost surely, 2^{1211209999919} is an apocalyptic number.

1211209999919 is a deficient number, since it is larger than the sum of its proper divisors (2627354041).

1211209999919 is an equidigital number, since it uses as much as digits as its factorization.

1211209999919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2627354040.

The product of its (nonzero) digits is 2125764, while the sum is 62.

The spelling of 1211209999919 in words is "one trillion, two hundred eleven billion, two hundred nine million, nine hundred ninety-nine thousand, nine hundred nineteen".