216257917 has 2 divisors, whose sum is σ = 216257918. Its totient is φ = 216257916.

The previous prime is 216257887. The next prime is 216257927. The reversal of 216257917 is 719752612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 108388921 + 107868996 = 10411^2 + 10386^2 .

It is a cyclic number.

It is not a de Polignac number, because 216257917 - 2¹¹ = 216255869 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216257917.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216257927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108128958 + 108128959.

It is an arithmetic number, because the mean of its divisors is an integer number (108128959).

Almost surely, 2^216257917 is an apocalyptic number.

It is an amenable number.

216257917 is a deficient number, since it is larger than the sum of its proper divisors (1).

216257917 is an equidigital number, since it uses as much as digits as its factorization.

216257917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52920, while the sum is 40.

The square root of 216257917 is about 14705.7103534647. The cubic root of 216257917 is about 600.2387170481.

The spelling of 216257917 in words is "two hundred sixteen million, two hundred fifty-seven thousand, nine hundred seventeen".