1806139 has 4 divisors (see below), whose sum is σ = 1808856. Its totient is φ = 1803424.

The previous prime is 1806137. The next prime is 1806143. The reversal of 1806139 is 9316081.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9316081 = 23 ⋅405047.

It is a cyclic number.

It is not a de Polignac number, because 1806139 - 2¹ = 1806137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1806137) 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, 387 + ... + 1939.

It is an arithmetic number, because the mean of its divisors is an integer number (452214).

2^1806139 is an apocalyptic number.

1806139 is a deficient number, since it is larger than the sum of its proper divisors (2717).

1806139 is a wasteful number, since it uses less digits than its factorization.

1806139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2716.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 1806139 is about 1343.9267093112. The cubic root of 1806139 is about 121.7821742441.

The spelling of 1806139 in words is "one million, eight hundred six thousand, one hundred thirty-nine".