20565213 has 4 divisors (see below), whose sum is σ = 27420288. Its totient is φ = 13710140.

The previous prime is 20565211. The next prime is 20565247. The reversal of 20565213 is 31256502.

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 a cyclic number.

It is not a de Polignac number, because 20565213 - 2¹ = 20565211 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565211) 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, 3427533 + ... + 3427538.

It is an arithmetic number, because the mean of its divisors is an integer number (6855072).

Almost surely, 2^20565213 is an apocalyptic number.

It is an amenable number.

20565213 is a deficient number, since it is larger than the sum of its proper divisors (6855075).

20565213 is an equidigital number, since it uses as much as digits as its factorization.

20565213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6855074.

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 20565213 is about 4534.8884220011. Note that the first 3 decimals coincide. The cubic root of 20565213 is about 273.9750852015.

The spelling of 20565213 in words is "twenty million, five hundred sixty-five thousand, two hundred thirteen".