20505469 has 2 divisors, whose sum is σ = 20505470. Its totient is φ = 20505468.

The previous prime is 20505467. The next prime is 20505473. The reversal of 20505469 is 96450502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18062500 + 2442969 = 4250^2 + 1563^2 .

It is a cyclic number.

It is not a de Polignac number, because 20505469 - 2¹ = 20505467 is a prime.

It is a super-2 number, since 2×20505469² = 840948517819922, which contains 22 as substring.

Together with 20505467, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20505469.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20505467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252734 + 10252735.

It is an arithmetic number, because the mean of its divisors is an integer number (10252735).

Almost surely, 2^20505469 is an apocalyptic number.

It is an amenable number.

20505469 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505469 is an equidigital number, since it uses as much as digits as its factorization.

20505469 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 20505469 is about 4528.2964788097. The cubic root of 20505469 is about 273.7095195316.

The spelling of 20505469 in words is "twenty million, five hundred five thousand, four hundred sixty-nine".