1213311999 has 4 divisors (see below), whose sum is σ = 1617749336. Its totient is φ = 808874664.

The previous prime is 1213311989. The next prime is 1213312019. The reversal of 1213311999 is 9991133121.

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

It is not a de Polignac number, because 1213311999 - 2¹³ = 1213303807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213311989) 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, 202218664 + ... + 202218669.

It is an arithmetic number, because the mean of its divisors is an integer number (404437334).

Almost surely, 2^1213311999 is an apocalyptic number.

1213311999 is a deficient number, since it is larger than the sum of its proper divisors (404437337).

1213311999 is an equidigital number, since it uses as much as digits as its factorization.

1213311999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404437336.

The product of its digits is 13122, while the sum is 39.

The square root of 1213311999 is about 34832.6283676670. The cubic root of 1213311999 is about 1066.5736026988.

The spelling of 1213311999 in words is "one billion, two hundred thirteen million, three hundred eleven thousand, nine hundred ninety-nine".