215685117 has 6 divisors (see below), whose sum is σ = 311545182. Its totient is φ = 143790072.

The previous prime is 215685101. The next prime is 215685139. The reversal of 215685117 is 711586512.

It can be written as a sum of positive squares in only one way, i.e., 123409881 + 92275236 = 11109^2 + 9606^2 .

It is not a de Polignac number, because 215685117 - 2⁴ = 215685101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215685157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11982498 + ... + 11982515.

It is an arithmetic number, because the mean of its divisors is an integer number (51924197).

Almost surely, 2^215685117 is an apocalyptic number.

It is an amenable number.

215685117 is a deficient number, since it is larger than the sum of its proper divisors (95860065).

215685117 is a wasteful number, since it uses less digits than its factorization.

215685117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23965019 (or 23965016 counting only the distinct ones).

The product of its digits is 16800, while the sum is 36.

The square root of 215685117 is about 14686.2220124850. Note that the first 3 decimals coincide. The cubic root of 215685117 is about 599.7082998747.

The spelling of 215685117 in words is "two hundred fifteen million, six hundred eighty-five thousand, one hundred seventeen".