20845569 has 4 divisors (see below), whose sum is σ = 27794096. Its totient is φ = 13897044.

The previous prime is 20845543. The next prime is 20845579. The reversal of 20845569 is 96554802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20845569 - 2⁵ = 20845537 is a prime.

It is a super-2 number, since 2×20845569² = 869075493867522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20845579) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3474259 + ... + 3474264.

It is an arithmetic number, because the mean of its divisors is an integer number (6948524).

Almost surely, 2^20845569 is an apocalyptic number.

It is an amenable number.

20845569 is a deficient number, since it is larger than the sum of its proper divisors (6948527).

20845569 is an equidigital number, since it uses as much as digits as its factorization.

20845569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6948526.

The product of its (nonzero) digits is 86400, while the sum is 39.

The square root of 20845569 is about 4565.6947992611. The cubic root of 20845569 is about 275.2144619070.

The spelling of 20845569 in words is "twenty million, eight hundred forty-five thousand, five hundred sixty-nine".