2181418 has 4 divisors (see below), whose sum is σ = 3272130. Its totient is φ = 1090708.

The previous prime is 2181379. The next prime is 2181419. The reversal of 2181418 is 8141812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1530169 + 651249 = 1237^2 + 807^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 2181392 and 2181401.

It is not an unprimeable number, because it can be changed into a prime (2181419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545353 + ... + 545356.

2^2181418 is an apocalyptic number.

2181418 is a deficient number, since it is larger than the sum of its proper divisors (1090712).

2181418 is a wasteful number, since it uses less digits than its factorization.

2181418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1090711.

The product of its digits is 512, while the sum is 25.

The square root of 2181418 is about 1476.9624233541. The cubic root of 2181418 is about 129.6919332592.

The spelling of 2181418 in words is "two million, one hundred eighty-one thousand, four hundred eighteen".