2155864 has 16 divisors (see below), whose sum is σ = 4173120. Its totient is φ = 1043040.

The previous prime is 2155861. The next prime is 2155877. The reversal of 2155864 is 4685512.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155861) 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, 4099 + ... + 4594.

It is an arithmetic number, because the mean of its divisors is an integer number (260820).

2^2155864 is an apocalyptic number.

It is an amenable number.

2155864 is a deficient number, since it is larger than the sum of its proper divisors (2017256).

2155864 is a wasteful number, since it uses less digits than its factorization.

2155864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8730 (or 8726 counting only the distinct ones).

The product of its digits is 9600, while the sum is 31.

The square root of 2155864 is about 1468.2860756678. The cubic root of 2155864 is about 129.1835218148.

The spelling of 2155864 in words is "two million, one hundred fifty-five thousand, eight hundred sixty-four".