1191216399 has 8 divisors (see below), whose sum is σ = 1590476160. Its totient is φ = 793050456.

The previous prime is 1191216361. The next prime is 1191216407. The reversal of 1191216399 is 9936121911.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1191216399 - 2²³ = 1182827791 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1191216399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1191216359) 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 in 7 ways as a sum of consecutive naturals, for example, 270909 + ... + 275270.

It is an arithmetic number, because the mean of its divisors is an integer number (198809520).

Almost surely, 2^1191216399 is an apocalyptic number.

1191216399 is a deficient number, since it is larger than the sum of its proper divisors (399259761).

1191216399 is an equidigital number, since it uses as much as digits as its factorization.

1191216399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 546909.

The product of its digits is 26244, while the sum is 42.

The square root of 1191216399 is about 34514.0029408355. The cubic root of 1191216399 is about 1060.0594481314.

The spelling of 1191216399 in words is "one billion, one hundred ninety-one million, two hundred sixteen thousand, three hundred ninety-nine".