2181356 has 12 divisors (see below), whose sum is σ = 3827880. Its totient is φ = 1087680.

The previous prime is 2181349. The next prime is 2181359. The reversal of 2181356 is 6531812.

It is not an unprimeable number, because it can be changed into a prime (2181359) 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, 2036 + ... + 2916.

It is an arithmetic number, because the mean of its divisors is an integer number (318990).

2^2181356 is an apocalyptic number.

It is an amenable number.

2181356 is a deficient number, since it is larger than the sum of its proper divisors (1646524).

2181356 is a wasteful number, since it uses less digits than its factorization.

2181356 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1504 (or 1502 counting only the distinct ones).

The product of its digits is 1440, while the sum is 26.

The square root of 2181356 is about 1476.9414341808. The cubic root of 2181356 is about 129.6907045514.

It can be divided in two parts, 21 and 81356, that multiplied together give a triangular number (1708476 = T₁₈₄₈).

The spelling of 2181356 in words is "two million, one hundred eighty-one thousand, three hundred fifty-six".