20561066 has 16 divisors (see below), whose sum is σ = 31394688. Its totient is φ = 10098000.

The previous prime is 20561053. The next prime is 20561069. The reversal of 20561066 is 66016502.

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20561069) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30776 + ... + 31436.

It is an arithmetic number, because the mean of its divisors is an integer number (1962168).

Almost surely, 2^20561066 is an apocalyptic number.

20561066 is a deficient number, since it is larger than the sum of its proper divisors (10833622).

20561066 is a wasteful number, since it uses less digits than its factorization.

20561066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 917.

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

The square root of 20561066 is about 4534.4311660891. The cubic root of 20561066 is about 273.9566681614.

Adding to 20561066 its reverse (66016502), we get a palindrome (86577568).

The spelling of 20561066 in words is "twenty million, five hundred sixty-one thousand, sixty-six".