20085561 has 12 divisors (see below), whose sum is σ = 29797092. Its totient is φ = 13028256.

The previous prime is 20085553. The next prime is 20085563. The reversal of 20085561 is 16558002.

20085561 is a `hidden beast` number, since 20 + 0 + 85 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 7617600 + 12467961 = 2760^2 + 3531^2 .

It is not a de Polignac number, because 20085561 - 2³ = 20085553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20085563) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29826 + ... + 30491.

It is an arithmetic number, because the mean of its divisors is an integer number (2483091).

Almost surely, 2^20085561 is an apocalyptic number.

It is an amenable number.

20085561 is a deficient number, since it is larger than the sum of its proper divisors (9711531).

20085561 is a wasteful number, since it uses less digits than its factorization.

20085561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60360 (or 60357 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 20085561 is about 4481.6917564688. The cubic root of 20085561 is about 271.8282914606.

It can be divided in two parts, 2008 and 5561, that added together give a square (7569 = 87²).

The spelling of 20085561 in words is "twenty million, eighty-five thousand, five hundred sixty-one".