1321378839 has 80 divisors (see below), whose sum is σ = 2295786240. Its totient is φ = 751628160.

The previous prime is 1321378829. The next prime is 1321378843. The reversal of 1321378839 is 9388731231.

It is a happy number.

It is not a de Polignac number, because 1321378839 - 2⁷ = 1321378711 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1321378794 and 1321378803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321378829) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 3680542 + ... + 3680900.

It is an arithmetic number, because the mean of its divisors is an integer number (28697328).

Almost surely, 2^1321378839 is an apocalyptic number.

1321378839 is a deficient number, since it is larger than the sum of its proper divisors (974407401).

1321378839 is an frugal number, since it uses more digits than its factorization.

1321378839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414 (or 390 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 1321378839 is about 36350.7749435965. The cubic root of 1321378839 is about 1097.3431303578.

The spelling of 1321378839 in words is "one billion, three hundred twenty-one million, three hundred seventy-eight thousand, eight hundred thirty-nine".