2215645 has 4 divisors (see below), whose sum is σ = 2658780. Its totient is φ = 1772512.

The previous prime is 2215639. The next prime is 2215651. The reversal of 2215645 is 5465122.

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

It is an interprime number because it is at equal distance from previous prime (2215639) and next prime (2215651).

It can be written as a sum of positive squares in 2 ways, for example, as 605284 + 1610361 = 778^2 + 1269^2 .

It is a cyclic number.

It is not a de Polignac number, because 2215645 - 2⁹ = 2215133 is a prime.

It is a d-powerful number, because it can be written as 2 + 2⁵ + 1 + 5³ + 6³ + 4⁹ + 5⁹ .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221560 + ... + 221569.

It is an arithmetic number, because the mean of its divisors is an integer number (664695).

2^2215645 is an apocalyptic number.

It is an amenable number.

2215645 is a deficient number, since it is larger than the sum of its proper divisors (443135).

2215645 is an equidigital number, since it uses as much as digits as its factorization.

2215645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443134.

The product of its digits is 2400, while the sum is 25.

The square root of 2215645 is about 1488.5042828289. The cubic root of 2215645 is about 130.3667160400.

It can be divided in two parts, 22156 and 45, that added together give a square (22201 = 149²).

The spelling of 2215645 in words is "two million, two hundred fifteen thousand, six hundred forty-five".