215566 has 8 divisors (see below), whose sum is σ = 348264. Its totient is φ = 99480.

The previous prime is 215563. The next prime is 215573. The reversal of 215566 is 665512.

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

It is a self number, because there is not a number n which added to its sum of digits gives 215566.

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 3 ways as a sum of consecutive naturals, for example, 4120 + ... + 4171.

It is an arithmetic number, because the mean of its divisors is an integer number (43533).

2²¹⁵⁵⁶⁶ is an apocalyptic number.

215566 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

215566 is a deficient number, since it is larger than the sum of its proper divisors (132698).

215566 is a wasteful number, since it uses less digits than its factorization.

215566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8306.

The product of its digits is 1800, while the sum is 25.

The square root of 215566 is about 464.2908571144. The cubic root of 215566 is about 59.9597878706.

It can be divided in two parts, 21 and 5566, that multiplied together give a triangular number (116886 = T₄₈₃).

The spelling of 215566 in words is "two hundred fifteen thousand, five hundred sixty-six".