20509448969 has 2 divisors, whose sum is σ = 20509448970. Its totient is φ = 20509448968.

The previous prime is 20509448923. The next prime is 20509449007. The reversal of 20509448969 is 96984490502.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18758863369 + 1750585600 = 136963^2 + 41840^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20509448969 is a prime.

It is a super-2 number, since 2×20509448969² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20509448569) 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, 10254724484 + 10254724485.

It is an arithmetic number, because the mean of its divisors is an integer number (10254724485).

Almost surely, 2^20509448969 is an apocalyptic number.

It is an amenable number.

20509448969 is a deficient number, since it is larger than the sum of its proper divisors (1).

20509448969 is an equidigital number, since it uses as much as digits as its factorization.

20509448969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5598720, while the sum is 56.

The spelling of 20509448969 in words is "twenty billion, five hundred nine million, four hundred forty-eight thousand, nine hundred sixty-nine".