815666714257 has 2 divisors, whose sum is σ = 815666714258. Its totient is φ = 815666714256.

The previous prime is 815666714183. The next prime is 815666714281. The reversal of 815666714257 is 752417666518.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 479079928336 + 336586785921 = 692156^2 + 580161^2 .

It is a cyclic number.

It is not a de Polignac number, because 815666714257 - 2⁷ = 815666714129 is a prime.

It is not a weakly prime, because it can be changed into another prime (815666714297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407833357128 + 407833357129.

It is an arithmetic number, because the mean of its divisors is an integer number (407833357129).

Almost surely, 2^815666714257 is an apocalyptic number.

It is an amenable number.

815666714257 is a deficient number, since it is larger than the sum of its proper divisors (1).

815666714257 is an equidigital number, since it uses as much as digits as its factorization.

815666714257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16934400, while the sum is 58.

The spelling of 815666714257 in words is "eight hundred fifteen billion, six hundred sixty-six million, seven hundred fourteen thousand, two hundred fifty-seven".