2181236 has 12 divisors (see below), whose sum is σ = 4041828. Its totient is φ = 1026432.

The previous prime is 2181233. The next prime is 2181247. The reversal of 2181236 is 6321812.

It can be written as a sum of positive squares in 2 ways, for example, as 2016400 + 164836 = 1420^2 + 406^2 .

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181233) 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, 15971 + ... + 16106.

It is an arithmetic number, because the mean of its divisors is an integer number (336819).

2^2181236 is an apocalyptic number.

It is an amenable number.

2181236 is a deficient number, since it is larger than the sum of its proper divisors (1860592).

2181236 is a wasteful number, since it uses less digits than its factorization.

2181236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32098 (or 32096 counting only the distinct ones).

The product of its digits is 576, while the sum is 23.

The square root of 2181236 is about 1476.9008091270. The cubic root of 2181236 is about 129.6883263411.

Adding to 2181236 its product of digits (576), we get a palindrome (2181812).

The spelling of 2181236 in words is "two million, one hundred eighty-one thousand, two hundred thirty-six".