231218857 has 2 divisors, whose sum is σ = 231218858. Its totient is φ = 231218856.

The previous prime is 231218851. The next prime is 231218861. The reversal of 231218857 is 758812132.

231218857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161061481 + 70157376 = 12691^2 + 8376^2 .

It is a cyclic number.

It is not a de Polignac number, because 231218857 - 2¹⁵ = 231186089 is a prime.

It is not a weakly prime, because it can be changed into another prime (231218851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115609428 + 115609429.

It is an arithmetic number, because the mean of its divisors is an integer number (115609429).

Almost surely, 2^231218857 is an apocalyptic number.

It is an amenable number.

231218857 is a deficient number, since it is larger than the sum of its proper divisors (1).

231218857 is an equidigital number, since it uses as much as digits as its factorization.

231218857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 37.

The square root of 231218857 is about 15205.8823157356. The cubic root of 231218857 is about 613.7729578564.

The spelling of 231218857 in words is "two hundred thirty-one million, two hundred eighteen thousand, eight hundred fifty-seven".