2105639 has 4 divisors (see below), whose sum is σ = 2114280. Its totient is φ = 2097000.

The previous prime is 2105611. The next prime is 2105641. The reversal of 2105639 is 9365012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2105639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2105669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3944 + ... + 4445.

It is an arithmetic number, because the mean of its divisors is an integer number (528570).

2^2105639 is an apocalyptic number.

2105639 is a deficient number, since it is larger than the sum of its proper divisors (8641).

2105639 is an equidigital number, since it uses as much as digits as its factorization.

2105639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8640.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 2105639 is about 1451.0820100876. The cubic root of 2105639 is about 128.1724360543.

It can be divided in two parts, 2105 and 639, that added together give a cube (2744 = 14³).

The spelling of 2105639 in words is "two million, one hundred five thousand, six hundred thirty-nine".