215989865 has 32 divisors (see below), whose sum is σ = 329312256. Its totient is φ = 132295680.

The previous prime is 215989861. The next prime is 215989877. The reversal of 215989865 is 568989512.

It is not a de Polignac number, because 215989865 - 2² = 215989861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215989861) 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 31 ways as a sum of consecutive naturals, for example, 6449 + ... + 21761.

It is an arithmetic number, because the mean of its divisors is an integer number (10291008).

Almost surely, 2^215989865 is an apocalyptic number.

It is an amenable number.

215989865 is a deficient number, since it is larger than the sum of its proper divisors (113322391).

215989865 is a wasteful number, since it uses less digits than its factorization.

215989865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15369.

The product of its digits is 1555200, while the sum is 53.

The square root of 215989865 is about 14696.5936529524. The cubic root of 215989865 is about 599.9906155940.

The spelling of 215989865 in words is "two hundred fifteen million, nine hundred eighty-nine thousand, eight hundred sixty-five".