1213615321 has 4 divisors (see below), whose sum is σ = 1218961872. Its totient is φ = 1208268772.

The previous prime is 1213615259. The next prime is 1213615327. The reversal of 1213615321 is 1235163121.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213615321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213615327) 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, 2672935 + ... + 2673388.

It is an arithmetic number, because the mean of its divisors is an integer number (304740468).

Almost surely, 2^1213615321 is an apocalyptic number.

It is an amenable number.

1213615321 is a deficient number, since it is larger than the sum of its proper divisors (5346551).

1213615321 is an equidigital number, since it uses as much as digits as its factorization.

1213615321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5346550.

The product of its digits is 1080, while the sum is 25.

The square root of 1213615321 is about 34836.9820880053. The cubic root of 1213615321 is about 1066.6624746689.

Adding to 1213615321 its reverse (1235163121), we get a palindrome (2448778442).

The spelling of 1213615321 in words is "one billion, two hundred thirteen million, six hundred fifteen thousand, three hundred twenty-one".