20017061581 has 12 divisors (see below), whose sum is σ = 22033351900. Its totient is φ = 18171584640.

The previous prime is 20017061549. The next prime is 20017061591. The reversal of 20017061581 is 18516071002.

It can be written as a sum of positive squares in 2 ways, for example, as 837581481 + 19179480100 = 28941^2 + 138490^2 .

It is not a de Polignac number, because 20017061581 - 2⁵ = 20017061549 is a prime.

It is a super-2 number, since 2×20017061581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20017061501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30876 + ... + 202453.

Almost surely, 2^20017061581 is an apocalyptic number.

It is an amenable number.

20017061581 is a deficient number, since it is larger than the sum of its proper divisors (2016290319).

20017061581 is a wasteful number, since it uses less digits than its factorization.

20017061581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234060 (or 234049 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 31.

The spelling of 20017061581 in words is "twenty billion, seventeen million, sixty-one thousand, five hundred eighty-one".