1309391328 has 144 divisors (see below), whose sum is σ = 4023930960. Its totient is φ = 371718144.

The previous prime is 1309391287. The next prime is 1309391329. The reversal of 1309391328 is 8231939031.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1309391329) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 812988 + ... + 814596.

It is an arithmetic number, because the mean of its divisors is an integer number (27943965).

Almost surely, 2^1309391328 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1309391328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2011965480).

1309391328 is an abundant number, since it is smaller than the sum of its proper divisors (2714539632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1309391328 is a wasteful number, since it uses less digits than its factorization.

1309391328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1809 (or 1794 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 39.

The square root of 1309391328 is about 36185.5126811822. The cubic root of 1309391328 is about 1094.0146896461.

The spelling of 1309391328 in words is "one billion, three hundred nine million, three hundred ninety-one thousand, three hundred twenty-eight".