20688315181 has 2 divisors, whose sum is σ = 20688315182. Its totient is φ = 20688315180.

The previous prime is 20688315143. The next prime is 20688315203. The reversal of 20688315181 is 18151388602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19609521156 + 1078794025 = 140034^2 + 32845^2 .

It is a cyclic number.

It is not a de Polignac number, because 20688315181 - 2¹¹ = 20688313133 is a prime.

It is a super-2 number, since 2×20688315181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20688315881) 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 as a sum of consecutive naturals, namely, 10344157590 + 10344157591.

It is an arithmetic number, because the mean of its divisors is an integer number (10344157591).

Almost surely, 2^20688315181 is an apocalyptic number.

It is an amenable number.

20688315181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20688315181 is an equidigital number, since it uses as much as digits as its factorization.

20688315181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 92160, while the sum is 43.

The spelling of 20688315181 in words is "twenty billion, six hundred eighty-eight million, three hundred fifteen thousand, one hundred eighty-one".