20564617 has 4 divisors (see below), whose sum is σ = 20575440. Its totient is φ = 20553796.

The previous prime is 20564603. The next prime is 20564623. The reversal of 20564617 is 71646502.

It is a happy number.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 71646502 = 2 ⋅35823251.

It is a cyclic number.

It is not a de Polignac number, because 20564617 - 2¹⁹ = 20040329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20564317) 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, 1723 + ... + 6640.

It is an arithmetic number, because the mean of its divisors is an integer number (5143860).

Almost surely, 2^20564617 is an apocalyptic number.

It is an amenable number.

20564617 is a deficient number, since it is larger than the sum of its proper divisors (10823).

20564617 is an equidigital number, since it uses as much as digits as its factorization.

20564617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10822.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 20564617 is about 4534.8227087726. The cubic root of 20564617 is about 273.9724384872.

The spelling of 20564617 in words is "twenty million, five hundred sixty-four thousand, six hundred seventeen".