218552989 has 4 divisors (see below), whose sum is σ = 218583900. Its totient is φ = 218522080.

The previous prime is 218552987. The next prime is 218553059. The reversal of 218552989 is 989255812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 104960025 + 113592964 = 10245^2 + 10658^2 .

It is a cyclic number.

It is not a de Polignac number, because 218552989 - 2¹ = 218552987 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218552987) 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, 969 + ... + 20929.

It is an arithmetic number, because the mean of its divisors is an integer number (54645975).

Almost surely, 2^218552989 is an apocalyptic number.

It is an amenable number.

218552989 is a deficient number, since it is larger than the sum of its proper divisors (30911).

218552989 is a wasteful number, since it uses less digits than its factorization.

218552989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30910.

The product of its digits is 518400, while the sum is 49.

The square root of 218552989 is about 14783.5377701009. The cubic root of 218552989 is about 602.3546261753.

The spelling of 218552989 in words is "two hundred eighteen million, five hundred fifty-two thousand, nine hundred eighty-nine".