1686139 has 12 divisors (see below), whose sum is σ = 2113104. Its totient is φ = 1333584.

The previous prime is 1686137. The next prime is 1686143. The reversal of 1686139 is 9316861.

It is not a de Polignac number, because 1686139 - 2¹ = 1686137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1686133) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 687 + ... + 1960.

It is an arithmetic number, because the mean of its divisors is an integer number (176092).

2^1686139 is an apocalyptic number.

1686139 is a deficient number, since it is larger than the sum of its proper divisors (426965).

1686139 is a wasteful number, since it uses less digits than its factorization.

1686139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2674 (or 2667 counting only the distinct ones).

The product of its digits is 7776, while the sum is 34.

The square root of 1686139 is about 1298.5141508663. The cubic root of 1686139 is about 119.0230635805.

It can be divided in two parts, 16861 and 39, that added together give a square (16900 = 130²).

The spelling of 1686139 in words is "one million, six hundred eighty-six thousand, one hundred thirty-nine".