218689969 has 4 divisors (see below), whose sum is σ = 221685796. Its totient is φ = 215694144.

The previous prime is 218689967. The next prime is 218689979. The reversal of 218689969 is 969986812.

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

It can be written as a sum of positive squares in 2 ways, for example, as 95746225 + 122943744 = 9785^2 + 11088^2 .

It is a cyclic number.

It is not a de Polignac number, because 218689969 - 2¹ = 218689967 is a prime.

It is a super-2 number, since 2×218689969² = 95650605082441922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218689967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1497804 + ... + 1497949.

It is an arithmetic number, because the mean of its divisors is an integer number (55421449).

Almost surely, 2^218689969 is an apocalyptic number.

It is an amenable number.

218689969 is a deficient number, since it is larger than the sum of its proper divisors (2995827).

218689969 is an equidigital number, since it uses as much as digits as its factorization.

218689969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2995826.

The product of its digits is 3359232, while the sum is 58.

The square root of 218689969 is about 14788.1699002953. The cubic root of 218689969 is about 602.4804435725.

The spelling of 218689969 in words is "two hundred eighteen million, six hundred eighty-nine thousand, nine hundred sixty-nine".