213516665 has 8 divisors (see below), whose sum is σ = 256324488. Its totient is φ = 170743680.

The previous prime is 213516637. The next prime is 213516673. The reversal of 213516665 is 566615312.

It can be written as a sum of positive squares in 4 ways, for example, as 9369721 + 204146944 = 3061^2 + 14288^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 213516665 - 2¹² = 213512569 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7535 + ... + 21995.

It is an arithmetic number, because the mean of its divisors is an integer number (32040561).

Almost surely, 2^213516665 is an apocalyptic number.

It is an amenable number.

213516665 is a deficient number, since it is larger than the sum of its proper divisors (42807823).

213516665 is a wasteful number, since it uses less digits than its factorization.

213516665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17419.

The product of its digits is 32400, while the sum is 35.

The square root of 213516665 is about 14612.2094496349. The cubic root of 213516665 is about 597.6917470756.

The spelling of 213516665 in words is "two hundred thirteen million, five hundred sixteen thousand, six hundred sixty-five".