21569065 has 12 divisors (see below), whose sum is σ = 30108996. Its totient is φ = 14790048.

The previous prime is 21569059. The next prime is 21569071. The reversal of 21569065 is 56096512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21569059) and next prime (21569071).

It can be written as a sum of positive squares in 2 ways, for example, as 11909401 + 9659664 = 3451^2 + 3108^2 .

It is not a de Polignac number, because 21569065 - 2²¹ = 19471913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21569065.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43774 + ... + 44263.

It is an arithmetic number, because the mean of its divisors is an integer number (2509083).

Almost surely, 2^21569065 is an apocalyptic number.

It is an amenable number.

21569065 is a deficient number, since it is larger than the sum of its proper divisors (8539931).

21569065 is an equidigital number, since it uses as much as digits as its factorization.

21569065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88056 (or 88049 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 34.

The square root of 21569065 is about 4644.2507468913. The cubic root of 21569065 is about 278.3623150606.

The spelling of 21569065 in words is "twenty-one million, five hundred sixty-nine thousand, sixty-five".