218891 has 8 divisors (see below), whose sum is σ = 236544. Its totient is φ = 201960.

The previous prime is 218887. The next prime is 218923. The reversal of 218891 is 198812.

218891 = T₁₀₃ + T₁₀₄ + ... + T₁₃₃.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 218891 - 2² = 218887 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 560 + ... + 866.

It is an arithmetic number, because the mean of its divisors is an integer number (29568).

2²¹⁸⁸⁹¹ is an apocalyptic number.

218891 is a deficient number, since it is larger than the sum of its proper divisors (17653).

218891 is a wasteful number, since it uses less digits than its factorization.

218891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361.

The product of its digits is 1152, while the sum is 29.

The square root of 218891 is about 467.8578844051. The cubic root of 218891 is about 60.2664997309.

The spelling of 218891 in words is "two hundred eighteen thousand, eight hundred ninety-one".