213665 has 8 divisors (see below), whose sum is σ = 259008. Its totient is φ = 169200.

The previous prime is 213659. The next prime is 213713. The reversal of 213665 is 566312.

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

It is not a de Polignac number, because 213665 - 2⁴ = 213649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213665.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 614 + ... + 896.

It is an arithmetic number, because the mean of its divisors is an integer number (32376).

2²¹³⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

213665 is a deficient number, since it is larger than the sum of its proper divisors (45343).

213665 is a wasteful number, since it uses less digits than its factorization.

213665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439.

The product of its digits is 1080, while the sum is 23.

The square root of 213665 is about 462.2391156101. The cubic root of 213665 is about 59.7830125161.

Adding to 213665 its reverse (566312), we get a palindrome (779977).

It can be divided in two parts, 213 and 665, that added together give a palindrome (878).

The spelling of 213665 in words is "two hundred thirteen thousand, six hundred sixty-five".