2155869 has 8 divisors (see below), whose sum is σ = 3193920. Its totient is φ = 1437228.

The previous prime is 2155861. The next prime is 2155877. The reversal of 2155869 is 9685512.

It is a happy number.

2155869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (2155861) and next prime (2155877).

It is not a de Polignac number, because 2155869 - 2³ = 2155861 is a prime.

It is a super-2 number, since 2×2155869² = 9295542290322, which contains 22 as substring.

2155869 is a lucky number.

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 pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39897 + ... + 39950.

It is an arithmetic number, because the mean of its divisors is an integer number (399240).

2^2155869 is an apocalyptic number.

It is an amenable number.

2155869 is a deficient number, since it is larger than the sum of its proper divisors (1038051).

2155869 is an equidigital number, since it uses as much as digits as its factorization.

2155869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79856 (or 79850 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 2155869 is about 1468.2877783323. The cubic root of 2155869 is about 129.1836216846.

It can be divided in two parts, 215 and 5869, that added together give a square (6084 = 78²).

The spelling of 2155869 in words is "two million, one hundred fifty-five thousand, eight hundred sixty-nine".