2166545 has 4 divisors (see below), whose sum is σ = 2599860. Its totient is φ = 1733232.

The previous prime is 2166533. The next prime is 2166547. The reversal of 2166545 is 5456612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 707281 + 1459264 = 841^2 + 1208^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166545 - 2⁴ = 2166529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2166547) 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, 216650 + ... + 216659.

It is an arithmetic number, because the mean of its divisors is an integer number (649965).

2^2166545 is an apocalyptic number.

It is an amenable number.

2166545 is a deficient number, since it is larger than the sum of its proper divisors (433315).

2166545 is an equidigital number, since it uses as much as digits as its factorization.

2166545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433314.

The product of its digits is 7200, while the sum is 29.

The square root of 2166545 is about 1471.9188156960. The cubic root of 2166545 is about 129.3965124830.

It can be divided in two parts, 21 and 66545, that added together give a palindrome (66566).

The spelling of 2166545 in words is "two million, one hundred sixty-six thousand, five hundred forty-five".