1323131021 has 4 divisors (see below), whose sum is σ = 1323203772. Its totient is φ = 1323058272.

The previous prime is 1323130999. The next prime is 1323131039. The reversal of 1323131021 is 1201313231.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1201313231 = 43 ⋅27937517.

It can be written as a sum of positive squares in 2 ways, for example, as 817330921 + 505800100 = 28589^2 + 22490^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1323131021 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 (1323131071) 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, 18041 + ... + 54513.

It is an arithmetic number, because the mean of its divisors is an integer number (330800943).

Almost surely, 2^1323131021 is an apocalyptic number.

It is an amenable number.

1323131021 is a deficient number, since it is larger than the sum of its proper divisors (72751).

1323131021 is an equidigital number, since it uses as much as digits as its factorization.

1323131021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72750.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1323131021 is about 36374.8679860147. The cubic root of 1323131021 is about 1097.8279511072.

Adding to 1323131021 its reverse (1201313231), we get a palindrome (2524444252).

The spelling of 1323131021 in words is "one billion, three hundred twenty-three million, one hundred thirty-one thousand, twenty-one".