1218181 has 4 divisors (see below), whose sum is σ = 1230112. Its totient is φ = 1206252.

The previous prime is 1218179. The next prime is 1218197. The reversal of 1218181 is 1818121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1818121 = 743 ⋅2447.

It is a cyclic number.

It is not a de Polignac number, because 1218181 - 2¹ = 1218179 is a prime.

It is a super-2 number, since 2×1218181² = 2967929897522, which contains 22 as substring.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218121) 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, 5811 + ... + 6016.

It is an arithmetic number, because the mean of its divisors is an integer number (307528).

2^1218181 is an apocalyptic number.

It is an amenable number.

1218181 is a deficient number, since it is larger than the sum of its proper divisors (11931).

1218181 is a wasteful number, since it uses less digits than its factorization.

1218181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11930.

The product of its digits is 128, while the sum is 22.

The square root of 1218181 is about 1103.7123719520. The cubic root of 1218181 is about 106.7998412562.

The spelling of 1218181 in words is "one million, two hundred eighteen thousand, one hundred eighty-one".