1389439840 has 48 divisors (see below), whose sum is σ = 3388452480. Its totient is φ = 537845760.

The previous prime is 1389439823. The next prime is 1389439861. The reversal of 1389439840 is 489349831.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135105 + ... + 145024.

It is an arithmetic number, because the mean of its divisors is an integer number (70592760).

Almost surely, 2^1389439840 is an apocalyptic number.

1389439840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1389439840 is an abundant number, since it is smaller than the sum of its proper divisors (1999012640).

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

1389439840 is a wasteful number, since it uses less digits than its factorization.

1389439840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280175 (or 280167 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 49.

The square root of 1389439840 is about 37275.1906769100. The cubic root of 1389439840 is about 1115.8690938980.

Subtracting from 1389439840 its reverse (489349831), we obtain a palindrome (900090009).

The spelling of 1389439840 in words is "one billion, three hundred eighty-nine million, four hundred thirty-nine thousand, eight hundred forty".