1687378256349 has 4 divisors (see below), whose sum is σ = 2249837675136. Its totient is φ = 1124918837564.

The previous prime is 1687378256329. The next prime is 1687378256353. The reversal of 1687378256349 is 9436528737861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1687378256349 - 2²¹ = 1687376159197 is a prime.

It is a super-3 number, since 3×1687378256349³ (a number of 38 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687378256329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 281229709389 + ... + 281229709394.

It is an arithmetic number, because the mean of its divisors is an integer number (562459418784).

Almost surely, 2^{1687378256349} is an apocalyptic number.

It is an amenable number.

1687378256349 is a deficient number, since it is larger than the sum of its proper divisors (562459418787).

1687378256349 is an equidigital number, since it uses as much as digits as its factorization.

1687378256349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562459418786.

The product of its digits is 365783040, while the sum is 69.

The spelling of 1687378256349 in words is "one trillion, six hundred eighty-seven billion, three hundred seventy-eight million, two hundred fifty-six thousand, three hundred forty-nine".