1389991806 has 32 divisors (see below), whose sum is σ = 3530138880. Its totient is φ = 397140408.

The previous prime is 1389991783. The next prime is 1389991831. The reversal of 1389991806 is 6081999831.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1838236 + ... + 1838991.

It is an arithmetic number, because the mean of its divisors is an integer number (110316840).

Almost surely, 2^1389991806 is an apocalyptic number.

1389991806 is an abundant number, since it is smaller than the sum of its proper divisors (2140147074).

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

1389991806 is a wasteful number, since it uses less digits than its factorization.

1389991806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3677245 (or 3677239 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 54.

The square root of 1389991806 is about 37282.5938743538. The cubic root of 1389991806 is about 1116.0168369526.

The spelling of 1389991806 in words is "one billion, three hundred eighty-nine million, nine hundred ninety-one thousand, eight hundred six".