20564143 has 4 divisors (see below), whose sum is σ = 20574000. Its totient is φ = 20554288.

The previous prime is 20564123. The next prime is 20564147. The reversal of 20564143 is 34146502.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20564143 - 2¹⁷ = 20433071 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20564147) 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, 430 + ... + 6427.

It is an arithmetic number, because the mean of its divisors is an integer number (5143500).

Almost surely, 2^20564143 is an apocalyptic number.

20564143 is a deficient number, since it is larger than the sum of its proper divisors (9857).

20564143 is an equidigital number, since it uses as much as digits as its factorization.

20564143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9856.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20564143 is about 4534.7704462299. The cubic root of 20564143 is about 273.9703335135.

The spelling of 20564143 in words is "twenty million, five hundred sixty-four thousand, one hundred forty-three".