2155806 has 24 divisors (see below), whose sum is σ = 4700280. Its totient is φ = 714096.

The previous prime is 2155799. The next prime is 2155837. The reversal of 2155806 is 6085512.

It is a self number, because there is not a number n which added to its sum of digits gives 2155806.

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, 3861 + ... + 4383.

It is an arithmetic number, because the mean of its divisors is an integer number (195845).

2^2155806 is an apocalyptic number.

2155806 is an abundant number, since it is smaller than the sum of its proper divisors (2544474).

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

2155806 is a wasteful number, since it uses less digits than its factorization.

2155806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 760 (or 757 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 2155806 is about 1468.2663246155. The cubic root of 2155806 is about 129.1823633138.

The spelling of 2155806 in words is "two million, one hundred fifty-five thousand, eight hundred six".