20512169 has 2 divisors, whose sum is σ = 20512170. Its totient is φ = 20512168.

The previous prime is 20512139. The next prime is 20512181. The reversal of 20512169 is 96121502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17952169 + 2560000 = 4237^2 + 1600^2 .

It is a cyclic number.

It is not a de Polignac number, because 20512169 - 2⁸ = 20511913 is a prime.

It is a super-2 number, since 2×20512169² = 841498154169122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20512139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10256084 + 10256085.

It is an arithmetic number, because the mean of its divisors is an integer number (10256085).

Almost surely, 2^20512169 is an apocalyptic number.

It is an amenable number.

20512169 is a deficient number, since it is larger than the sum of its proper divisors (1).

20512169 is an equidigital number, since it uses as much as digits as its factorization.

20512169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 20512169 is about 4529.0362109394. The cubic root of 20512169 is about 273.7393270930.

The spelling of 20512169 in words is "twenty million, five hundred twelve thousand, one hundred sixty-nine".