20531257169 has 2 divisors, whose sum is σ = 20531257170. Its totient is φ = 20531257168.

The previous prime is 20531257141. The next prime is 20531257247. The reversal of 20531257169 is 96175213502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15678044944 + 4853212225 = 125212^2 + 69665^2 .

It is a cyclic number.

It is not a de Polignac number, because 20531257169 - 2³² = 16236289873 is a prime.

It is a super-2 number, since 2×20531257169² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20531257469) 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, 10265628584 + 10265628585.

It is an arithmetic number, because the mean of its divisors is an integer number (10265628585).

Almost surely, 2^20531257169 is an apocalyptic number.

It is an amenable number.

20531257169 is a deficient number, since it is larger than the sum of its proper divisors (1).

20531257169 is an equidigital number, since it uses as much as digits as its factorization.

20531257169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 113400, while the sum is 41.

The spelling of 20531257169 in words is "twenty billion, five hundred thirty-one million, two hundred fifty-seven thousand, one hundred sixty-nine".