999971000257 has 2 divisors, whose sum is σ = 999971000258. Its totient is φ = 999971000256.

The previous prime is 999971000191. The next prime is 999971000311. The reversal of 999971000257 is 752000179999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 688914940081 + 311056060176 = 830009^2 + 557724^2 .

It is an emirp because it is prime and its reverse (752000179999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999971000257 - 2¹¹ = 999970998209 is a prime.

It is not a weakly prime, because it can be changed into another prime (999971004257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499985500128 + 499985500129.

It is an arithmetic number, because the mean of its divisors is an integer number (499985500129).

Almost surely, 2^999971000257 is an apocalyptic number.

It is an amenable number.

999971000257 is a deficient number, since it is larger than the sum of its proper divisors (1).

999971000257 is an equidigital number, since it uses as much as digits as its factorization.

999971000257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3214890, while the sum is 58.

The spelling of 999971000257 in words is "nine hundred ninety-nine billion, nine hundred seventy-one million, two hundred fifty-seven", and thus it is an aban number.