1687715257 has 2 divisors, whose sum is σ = 1687715258. Its totient is φ = 1687715256.

The previous prime is 1687715231. The next prime is 1687715279. The reversal of 1687715257 is 7525177861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1687237776 + 477481 = 41076^2 + 691^2 .

It is a cyclic number.

It is not a de Polignac number, because 1687715257 - 2¹⁵ = 1687682489 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1687715257.

It is not a weakly prime, because it can be changed into another prime (1687715287) 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, 843857628 + 843857629.

It is an arithmetic number, because the mean of its divisors is an integer number (843857629).

Almost surely, 2^1687715257 is an apocalyptic number.

It is an amenable number.

1687715257 is a deficient number, since it is larger than the sum of its proper divisors (1).

1687715257 is an equidigital number, since it uses as much as digits as its factorization.

1687715257 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 823200, while the sum is 49.

The square root of 1687715257 is about 41081.8117541084. The cubic root of 1687715257 is about 1190.6014089258.

The spelling of 1687715257 in words is "one billion, six hundred eighty-seven million, seven hundred fifteen thousand, two hundred fifty-seven".