218220817 has 2 divisors, whose sum is σ = 218220818. Its totient is φ = 218220816.

The previous prime is 218220773. The next prime is 218220839. The reversal of 218220817 is 718022812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207619281 + 10601536 = 14409^2 + 3256^2 .

It is a cyclic number.

It is not a de Polignac number, because 218220817 - 2⁷ = 218220689 is a prime.

It is not a weakly prime, because it can be changed into another prime (218220617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109110408 + 109110409.

It is an arithmetic number, because the mean of its divisors is an integer number (109110409).

Almost surely, 2^218220817 is an apocalyptic number.

It is an amenable number.

218220817 is a deficient number, since it is larger than the sum of its proper divisors (1).

218220817 is an equidigital number, since it uses as much as digits as its factorization.

218220817 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 218220817 is about 14772.2989747703. The cubic root of 218220817 is about 602.0493046523.

The spelling of 218220817 in words is "two hundred eighteen million, two hundred twenty thousand, eight hundred seventeen".