1391338728 has 64 divisors (see below), whose sum is σ = 4162132800. Its totient is φ = 428103360.

The previous prime is 1391338723. The next prime is 1391338801. The reversal of 1391338728 is 8278331931.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1391338723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 244938 + ... + 250553.

It is an arithmetic number, because the mean of its divisors is an integer number (65033325).

Almost surely, 2^1391338728 is an apocalyptic number.

1391338728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1391338728 is an abundant number, since it is smaller than the sum of its proper divisors (2770794072).

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

1391338728 is a wasteful number, since it uses less digits than its factorization.

1391338728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495519 (or 495509 counting only the distinct ones).

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

The square root of 1391338728 is about 37300.6531846294. The cubic root of 1391338728 is about 1116.3771993538.

The spelling of 1391338728 in words is "one billion, three hundred ninety-one million, three hundred thirty-eight thousand, seven hundred twenty-eight".