216545 has 16 divisors (see below), whose sum is σ = 311040. Its totient is φ = 141504.

The previous prime is 216523. The next prime is 216551. The reversal of 216545 is 545612.

It is a cyclic number.

It is not a de Polignac number, because 216545 - 2⁶ = 216481 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 13.

It is a zygodrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 216545.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 671 + ... + 939.

It is an arithmetic number, because the mean of its divisors is an integer number (19440).

2²¹⁶⁵⁴⁵ is an apocalyptic number.

216545 is the 269-th octagonal number.

It is an amenable number.

216545 is a deficient number, since it is larger than the sum of its proper divisors (94495).

216545 is a wasteful number, since it uses less digits than its factorization.

216545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304.

The product of its digits is 1200, while the sum is 23.

The square root of 216545 is about 465.3439588090. The cubic root of 216545 is about 60.0504205805.

The spelling of 216545 in words is "two hundred sixteen thousand, five hundred forty-five".