2139805 has 12 divisors (see below), whose sum is σ = 2687580. Its totient is φ = 1635392.

The previous prime is 2139757. The next prime is 2139811. The reversal of 2139805 is 5089312.

It can be written as a sum of positive squares in 2 ways, for example, as 1375929 + 763876 = 1173^2 + 874^2 .

It is not a de Polignac number, because 2139805 - 2⁷ = 2139677 is a prime.

2139805 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2241 + ... + 3049.

It is an arithmetic number, because the mean of its divisors is an integer number (223965).

2^2139805 is an apocalyptic number.

It is an amenable number.

2139805 is a deficient number, since it is larger than the sum of its proper divisors (547775).

2139805 is an equidigital number, since it uses as much as digits as its factorization.

2139805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 860 (or 837 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 2139805 is about 1462.8072326865. The cubic root of 2139805 is about 128.8619599849.

The spelling of 2139805 in words is "two million, one hundred thirty-nine thousand, eight hundred five".