218412989 has 2 divisors, whose sum is σ = 218412990. Its totient is φ = 218412988.

The previous prime is 218412979. The next prime is 218413043. The reversal of 218412989 is 989214812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211469764 + 6943225 = 14542^2 + 2635^2 .

It is a cyclic number.

It is not a de Polignac number, because 218412989 - 2⁴ = 218412973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218412979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109206494 + 109206495.

It is an arithmetic number, because the mean of its divisors is an integer number (109206495).

Almost surely, 2^218412989 is an apocalyptic number.

It is an amenable number.

218412989 is a deficient number, since it is larger than the sum of its proper divisors (1).

218412989 is an equidigital number, since it uses as much as digits as its factorization.

218412989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 44.

The square root of 218412989 is about 14778.8020150484. The cubic root of 218412989 is about 602.2259805457.

The spelling of 218412989 in words is "two hundred eighteen million, four hundred twelve thousand, nine hundred eighty-nine".