216965857 has 2 divisors, whose sum is σ = 216965858. Its totient is φ = 216965856.

The previous prime is 216965851. The next prime is 216965887. The reversal of 216965857 is 758569612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116985856 + 99980001 = 10816^2 + 9999^2 .

It is a cyclic number.

It is not a de Polignac number, because 216965857 - 2²³ = 208577249 is a prime.

It is a super-3 number, since 3×216965857³ (a number of 26 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 216965857.

It is not a weakly prime, because it can be changed into another prime (216965851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108482928 + 108482929.

It is an arithmetic number, because the mean of its divisors is an integer number (108482929).

Almost surely, 2^216965857 is an apocalyptic number.

It is an amenable number.

216965857 is a deficient number, since it is larger than the sum of its proper divisors (1).

216965857 is an equidigital number, since it uses as much as digits as its factorization.

216965857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 49.

The square root of 216965857 is about 14729.7609281346. The cubic root of 216965857 is about 600.8929823486.

The spelling of 216965857 in words is "two hundred sixteen million, nine hundred sixty-five thousand, eight hundred fifty-seven".