218333881 has 2 divisors, whose sum is σ = 218333882. Its totient is φ = 218333880.

The previous prime is 218333851. The next prime is 218333891. The reversal of 218333881 is 188333812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142922025 + 75411856 = 11955^2 + 8684^2 .

It is a cyclic number.

It is not a de Polignac number, because 218333881 - 2⁵ = 218333849 is a prime.

It is a super-2 number, since 2×218333881² = 95339367185044322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 218333881.

It is not a weakly prime, because it can be changed into another prime (218333831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109166940 + 109166941.

It is an arithmetic number, because the mean of its divisors is an integer number (109166941).

Almost surely, 2^218333881 is an apocalyptic number.

It is an amenable number.

218333881 is a deficient number, since it is larger than the sum of its proper divisors (1).

218333881 is an equidigital number, since it uses as much as digits as its factorization.

218333881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 37.

The square root of 218333881 is about 14776.1253716934. The cubic root of 218333881 is about 602.1532641046.

The spelling of 218333881 in words is "two hundred eighteen million, three hundred thirty-three thousand, eight hundred eighty-one".