1213012321 has 4 divisors (see below), whose sum is σ = 1213096644. Its totient is φ = 1212928000.

The previous prime is 1213012303. The next prime is 1213012363. The reversal of 1213012321 is 1232103121.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 254243025 + 958769296 = 15945^2 + 30964^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213012321 - 2¹¹ = 1213010273 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1213012295 and 1213012304.

It is not an unprimeable number, because it can be changed into a prime (1213012621) 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, 14560 + ... + 51361.

It is an arithmetic number, because the mean of its divisors is an integer number (303274161).

Almost surely, 2^1213012321 is an apocalyptic number.

It is an amenable number.

1213012321 is a deficient number, since it is larger than the sum of its proper divisors (84323).

1213012321 is an equidigital number, since it uses as much as digits as its factorization.

1213012321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84322.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1213012321 is about 34828.3264168694. The cubic root of 1213012321 is about 1066.4857838571.

Adding to 1213012321 its reverse (1232103121), we get a palindrome (2445115442).

The spelling of 1213012321 in words is "one billion, two hundred thirteen million, twelve thousand, three hundred twenty-one".