1389028709 has 4 divisors (see below), whose sum is σ = 1422907500. Its totient is φ = 1355149920.

The previous prime is 1389028703. The next prime is 1389028727. The reversal of 1389028709 is 9078209831.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 139759684 + 1249269025 = 11822^2 + 35345^2 .

It is a cyclic number.

It is not a de Polignac number, because 1389028709 - 2⁸ = 1389028453 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1389028703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16939334 + ... + 16939415.

It is an arithmetic number, because the mean of its divisors is an integer number (355726875).

Almost surely, 2^1389028709 is an apocalyptic number.

It is an amenable number.

1389028709 is a deficient number, since it is larger than the sum of its proper divisors (33878791).

1389028709 is an equidigital number, since it uses as much as digits as its factorization.

1389028709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33878790.

The product of its (nonzero) digits is 217728, while the sum is 47.

The square root of 1389028709 is about 37269.6754614257. The cubic root of 1389028709 is about 1115.7590222898.

The spelling of 1389028709 in words is "one billion, three hundred eighty-nine million, twenty-eight thousand, seven hundred nine".