218495993 has 2 divisors, whose sum is σ = 218495994. Its totient is φ = 218495992.

The previous prime is 218495971. The next prime is 218496001. The reversal of 218495993 is 399594812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 133911184 + 84584809 = 11572^2 + 9197^2 .

It is a cyclic number.

It is not a de Polignac number, because 218495993 - 2¹⁴ = 218479609 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218494993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109247996 + 109247997.

It is an arithmetic number, because the mean of its divisors is an integer number (109247997).

Almost surely, 2^218495993 is an apocalyptic number.

It is an amenable number.

218495993 is a deficient number, since it is larger than the sum of its proper divisors (1).

218495993 is an equidigital number, since it uses as much as digits as its factorization.

218495993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 699840, while the sum is 50.

The square root of 218495993 is about 14781.6099596762. The cubic root of 218495993 is about 602.3022593339.

The spelling of 218495993 in words is "two hundred eighteen million, four hundred ninety-five thousand, nine hundred ninety-three".