218873257 has 2 divisors, whose sum is σ = 218873258. Its totient is φ = 218873256.

The previous prime is 218873243. The next prime is 218873261. The reversal of 218873257 is 752378812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 114404416 + 104468841 = 10696^2 + 10221^2 .

It is a cyclic number.

It is not a de Polignac number, because 218873257 - 2²³ = 210484649 is a prime.

It is not a weakly prime, because it can be changed into another prime (218873227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109436628 + 109436629.

It is an arithmetic number, because the mean of its divisors is an integer number (109436629).

Almost surely, 2^218873257 is an apocalyptic number.

It is an amenable number.

218873257 is a deficient number, since it is larger than the sum of its proper divisors (1).

218873257 is an equidigital number, since it uses as much as digits as its factorization.

218873257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 188160, while the sum is 43.

The square root of 218873257 is about 14794.3657180698. The cubic root of 218873257 is about 602.6487131399.

The spelling of 218873257 in words is "two hundred eighteen million, eight hundred seventy-three thousand, two hundred fifty-seven".