20868785181 has 12 divisors (see below), whose sum is σ = 30215406780. Its totient is φ = 13879474560.

The previous prime is 20868785167. The next prime is 20868785219. The reversal of 20868785181 is 18158786802.

It can be written as a sum of positive squares in 2 ways, for example, as 1349901081 + 19518884100 = 36741^2 + 139710^2 .

It is not a de Polignac number, because 20868785181 - 2⁷ = 20868785053 is a prime.

It is a super-2 number, since 2×20868785181² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20868780181) 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, 2750076 + ... + 2757653.

It is an arithmetic number, because the mean of its divisors is an integer number (2517950565).

Almost surely, 2^20868785181 is an apocalyptic number.

It is an amenable number.

20868785181 is a deficient number, since it is larger than the sum of its proper divisors (9346621599).

20868785181 is a wasteful number, since it uses less digits than its factorization.

20868785181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5508156 (or 5508153 counting only the distinct ones).

The product of its (nonzero) digits is 1720320, while the sum is 54.

The spelling of 20868785181 in words is "twenty billion, eight hundred sixty-eight million, seven hundred eighty-five thousand, one hundred eighty-one".