1331993321 has 4 divisors (see below), whose sum is σ = 1332355200. Its totient is φ = 1331631444.

The previous prime is 1331993261. The next prime is 1331993329. The reversal of 1331993321 is 1233991331.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1233991331 = 23 ⋅53651797.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331993321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1331993329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 175361 + ... + 182798.

It is an arithmetic number, because the mean of its divisors is an integer number (333088800).

Almost surely, 2^1331993321 is an apocalyptic number.

It is an amenable number.

1331993321 is a deficient number, since it is larger than the sum of its proper divisors (361879).

1331993321 is an equidigital number, since it uses as much as digits as its factorization.

1331993321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 361878.

The product of its digits is 13122, while the sum is 35.

The square root of 1331993321 is about 36496.4836799383. The cubic root of 1331993321 is about 1100.2735741042.

The spelling of 1331993321 in words is "one billion, three hundred thirty-one million, nine hundred ninety-three thousand, three hundred twenty-one".