1668501687 has 4 divisors (see below), whose sum is σ = 2224668920. Its totient is φ = 1112334456.

The previous prime is 1668501677. The next prime is 1668501721. The reversal of 1668501687 is 7861058661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7861058661 = 3 ⋅2620352887.

It is not a de Polignac number, because 1668501687 - 2¹² = 1668497591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668501677) 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 in 3 ways as a sum of consecutive naturals, for example, 278083612 + ... + 278083617.

It is an arithmetic number, because the mean of its divisors is an integer number (556167230).

Almost surely, 2^1668501687 is an apocalyptic number.

1668501687 is a deficient number, since it is larger than the sum of its proper divisors (556167233).

1668501687 is an equidigital number, since it uses as much as digits as its factorization.

1668501687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556167232.

The product of its (nonzero) digits is 483840, while the sum is 48.

The square root of 1668501687 is about 40847.2971810865. The cubic root of 1668501687 is about 1186.0660733351.

The spelling of 1668501687 in words is "one billion, six hundred sixty-eight million, five hundred one thousand, six hundred eighty-seven".