218390069 has 4 divisors (see below), whose sum is σ = 220843980. Its totient is φ = 215936160.

The previous prime is 218390057. The next prime is 218390099. The reversal of 218390069 is 960093812.

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 47748100 + 170641969 = 6910^2 + 13063^2 .

It is a cyclic number.

It is not a de Polignac number, because 218390069 - 2²⁰ = 217341493 is a prime.

It is a super-2 number, since 2×218390069² = 95388444475649522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218390099) 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, 1226822 + ... + 1226999.

It is an arithmetic number, because the mean of its divisors is an integer number (55210995).

Almost surely, 2^218390069 is an apocalyptic number.

It is an amenable number.

218390069 is a deficient number, since it is larger than the sum of its proper divisors (2453911).

218390069 is an equidigital number, since it uses as much as digits as its factorization.

218390069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2453910.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 218390069 is about 14778.0265597271. The cubic root of 218390069 is about 602.2049141821.

The spelling of 218390069 in words is "two hundred eighteen million, three hundred ninety thousand, sixty-nine".