215565 has 16 divisors (see below), whose sum is σ = 394368. Its totient is φ = 98496.

The previous prime is 215563. The next prime is 215573. The reversal of 215565 is 565512.

It is not a de Polignac number, because 215565 - 2¹ = 215563 is a prime.

215565 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 922 + ... + 1131.

It is an arithmetic number, because the mean of its divisors is an integer number (24648).

2²¹⁵⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

215565 is a deficient number, since it is larger than the sum of its proper divisors (178803).

215565 is a wasteful number, since it uses less digits than its factorization.

215565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2068.

The product of its digits is 1500, while the sum is 24.

The square root of 215565 is about 464.2897802020. The cubic root of 215565 is about 59.9596951536.

It can be divided in two parts, 215 and 565, that added together give a triangular number (780 = T₃₉).

The spelling of 215565 in words is "two hundred fifteen thousand, five hundred sixty-five".