21020569 has 8 divisors (see below), whose sum is σ = 21430400. Its totient is φ = 20614176.

The previous prime is 21020543. The next prime is 21020581. The reversal of 21020569 is 96502012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21020569 - 2⁵ = 21020537 is a prime.

It is a super-2 number, since 2×21020569² = 883728642167522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020509) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 13804 + ... + 15250.

It is an arithmetic number, because the mean of its divisors is an integer number (2678800).

Almost surely, 2^21020569 is an apocalyptic number.

It is an amenable number.

21020569 is a deficient number, since it is larger than the sum of its proper divisors (409831).

21020569 is a wasteful number, since it uses less digits than its factorization.

21020569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1719.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 21020569 is about 4584.8194075667. The cubic root of 21020569 is about 275.9824649295.

The spelling of 21020569 in words is "twenty-one million, twenty thousand, five hundred sixty-nine".