10821565 has 4 divisors (see below), whose sum is σ = 12985884. Its totient is φ = 8657248.

The previous prime is 10821541. The next prime is 10821589. The reversal of 10821565 is 56512801.

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 (10821541) and next prime (10821589).

It can be written as a sum of positive squares in 2 ways, for example, as 5812921 + 5008644 = 2411^2 + 2238^2 .

It is a cyclic number.

It is not a de Polignac number, because 10821565 - 2¹¹ = 10819517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1082152 + ... + 1082161.

It is an arithmetic number, because the mean of its divisors is an integer number (3246471).

Almost surely, 2^10821565 is an apocalyptic number.

It is an amenable number.

10821565 is a deficient number, since it is larger than the sum of its proper divisors (2164319).

10821565 is an equidigital number, since it uses as much as digits as its factorization.

10821565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2164318.

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 10821565 is about 3289.6147190819. The cubic root of 10821565 is about 221.1889145843.

The spelling of 10821565 in words is "ten million, eight hundred twenty-one thousand, five hundred sixty-five".