20566061 has 4 divisors (see below), whose sum is σ = 20585052. Its totient is φ = 20547072.

The previous prime is 20566057. The next prime is 20566069. The reversal of 20566061 is 16066502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16933225 + 3632836 = 4115^2 + 1906^2 .

It is a cyclic number.

It is not a de Polignac number, because 20566061 - 2² = 20566057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20566061.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20566069) 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, 7766 + ... + 10071.

It is an arithmetic number, because the mean of its divisors is an integer number (5146263).

Almost surely, 2^20566061 is an apocalyptic number.

It is an amenable number.

20566061 is a deficient number, since it is larger than the sum of its proper divisors (18991).

20566061 is a wasteful number, since it uses less digits than its factorization.

20566061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18990.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20566061 is about 4534.9819183763. The cubic root of 20566061 is about 273.9788509082.

It can be divided in two parts, 205 and 66061, that added together give a palindrome (66266).

The spelling of 20566061 in words is "twenty million, five hundred sixty-six thousand, sixty-one".