1329788641 has 4 divisors (see below), whose sum is σ = 1333354132. Its totient is φ = 1326223152.

The previous prime is 1329788561. The next prime is 1329788651. The reversal of 1329788641 is 1468879231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1468879231 = 31 ⋅47383201.

It can be written as a sum of positive squares in 2 ways, for example, as 711769041 + 618019600 = 26679^2 + 24860^2 .

It is a cyclic number.

It is not a de Polignac number, because 1329788641 - 2⁹ = 1329788129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1329788651) 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, 1782186 + ... + 1782931.

It is an arithmetic number, because the mean of its divisors is an integer number (333338533).

Almost surely, 2^1329788641 is an apocalyptic number.

It is an amenable number.

1329788641 is a deficient number, since it is larger than the sum of its proper divisors (3565491).

1329788641 is an equidigital number, since it uses as much as digits as its factorization.

1329788641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3565490.

The product of its digits is 580608, while the sum is 49.

The square root of 1329788641 is about 36466.2671656971. The cubic root of 1329788641 is about 1099.6661909982. Note that the first 3 decimals are identical.

The spelling of 1329788641 in words is "one billion, three hundred twenty-nine million, seven hundred eighty-eight thousand, six hundred forty-one".