2156805 has 48 divisors (see below), whose sum is σ = 4402944. Its totient is φ = 956160.

The previous prime is 2156801. The next prime is 2156809. The reversal of 2156805 is 5086512.

It is an interprime number because it is at equal distance from previous prime (2156801) and next prime (2156809).

It is not a de Polignac number, because 2156805 - 2² = 2156801 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2156801) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12832 + ... + 12998.

It is an arithmetic number, because the mean of its divisors is an integer number (91728).

2^2156805 is an apocalyptic number.

It is an amenable number.

2156805 is an abundant number, since it is smaller than the sum of its proper divisors (2246139).

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

2156805 is a wasteful number, since it uses less digits than its factorization.

2156805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226 (or 223 counting only the distinct ones).

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

The square root of 2156805 is about 1468.6064823498. The cubic root of 2156805 is about 129.2023145914.

The spelling of 2156805 in words is "two million, one hundred fifty-six thousand, eight hundred five".