1213111321 has 8 divisors (see below), whose sum is σ = 1243542888. Its totient is φ = 1182720000.

The previous prime is 1213111307. The next prime is 1213111327. The reversal of 1213111321 is 1231113121.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 567392400 + 645718921 = 23820^2 + 25411^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1213111321 - 2¹⁵ = 1213078553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213111295 and 1213111304.

It is not an unprimeable number, because it can be changed into a prime (1213111327) 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 in 7 ways as a sum of consecutive naturals, for example, 56401 + ... + 74881.

It is an arithmetic number, because the mean of its divisors is an integer number (155442861).

Almost surely, 2^1213111321 is an apocalyptic number.

It is an amenable number.

1213111321 is a deficient number, since it is larger than the sum of its proper divisors (30431567).

1213111321 is a wasteful number, since it uses less digits than its factorization.

1213111321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20123.

The product of its digits is 36, while the sum is 16.

The square root of 1213111321 is about 34829.7476447935. The cubic root of 1213111321 is about 1066.5147968134.

Adding to 1213111321 its reverse (1231113121), we get a palindrome (2444224442).

The spelling of 1213111321 in words is "one billion, two hundred thirteen million, one hundred eleven thousand, three hundred twenty-one".