21040569 has 27 divisors (see below), whose sum is σ = 33648069. Its totient is φ = 12660120.

The previous prime is 21040559. The next prime is 21040601. The reversal of 21040569 is 96504012.

The square root of 21040569 is 4587.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 21040569 - 2⁹ = 21040057 is a prime.

It is a super-2 number, since 2×21040569² = 885411087687522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21040519) by changing a digit.

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 26 ways as a sum of consecutive naturals, for example, 151302 + ... + 151440.

Almost surely, 2^21040569 is an apocalyptic number.

21040569 is the 4587-th square number.

21040569 is the 2294-th centered octagonal number.

It is an amenable number.

21040569 is a deficient number, since it is larger than the sum of its proper divisors (12607500).

21040569 is a wasteful number, since it uses less digits than its factorization.

21040569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306 (or 153 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The cubic root of 21040569 is about 276.0699649344.

It can be divided in two parts, 21040 and 569, that added together give a square (21609 = 147²).

The spelling of 21040569 in words is "twenty-one million, forty thousand, five hundred sixty-nine".