20343123257 has 2 divisors, whose sum is σ = 20343123258. Its totient is φ = 20343123256.

The previous prime is 20343123221. The next prime is 20343123347. The reversal of 20343123257 is 75232134302.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15877008016 + 4466115241 = 126004^2 + 66829^2 .

It is a cyclic number.

It is not a de Polignac number, because 20343123257 - 2⁶ = 20343123193 is a prime.

It is not a weakly prime, because it can be changed into another prime (20343122257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10171561628 + 10171561629.

It is an arithmetic number, because the mean of its divisors is an integer number (10171561629).

Almost surely, 2^20343123257 is an apocalyptic number.

It is an amenable number.

20343123257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20343123257 is an equidigital number, since it uses as much as digits as its factorization.

20343123257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 32.

Adding to 20343123257 its reverse (75232134302), we get a palindrome (95575257559).

The spelling of 20343123257 in words is "twenty billion, three hundred forty-three million, one hundred twenty-three thousand, two hundred fifty-seven".