1257166817 has 2 divisors, whose sum is σ = 1257166818. Its totient is φ = 1257166816.

The previous prime is 1257166717. The next prime is 1257166819. The reversal of 1257166817 is 7186617521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 651219361 + 605947456 = 25519^2 + 24616^2 .

It is a cyclic number.

It is not a de Polignac number, because 1257166817 - 2¹⁶ = 1257101281 is a prime.

It is a super-2 number, since 2×1257166817² = 3160936811531822978, which contains 22 as substring.

Together with 1257166819, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1257166819) 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, 628583408 + 628583409.

It is an arithmetic number, because the mean of its divisors is an integer number (628583409).

Almost surely, 2^1257166817 is an apocalyptic number.

It is an amenable number.

1257166817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1257166817 is an equidigital number, since it uses as much as digits as its factorization.

1257166817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 44.

The square root of 1257166817 is about 35456.5482950611. The cubic root of 1257166817 is about 1079.2721481871.

The spelling of 1257166817 in words is "one billion, two hundred fifty-seven million, one hundred sixty-six thousand, eight hundred seventeen".