1688671687 has 4 divisors (see below), whose sum is σ = 1699031800. Its totient is φ = 1678311576.

The previous prime is 1688671681. The next prime is 1688671717. The reversal of 1688671687 is 7861768861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7861768861 = 227 ⋅34633343.

It is a cyclic number.

It is not a de Polignac number, because 1688671687 - 2³ = 1688671679 is a prime.

It is a super-2 number, since 2×1688671687² = 5703224132950851938, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688671681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5179812 + ... + 5180137.

It is an arithmetic number, because the mean of its divisors is an integer number (424757950).

Almost surely, 2^1688671687 is an apocalyptic number.

1688671687 is a deficient number, since it is larger than the sum of its proper divisors (10360113).

1688671687 is a wasteful number, since it uses less digits than its factorization.

1688671687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10360112.

The product of its digits is 5419008, while the sum is 58.

The square root of 1688671687 is about 41093.4506582253. The cubic root of 1688671687 is about 1190.8262714755.

The spelling of 1688671687 in words is "one billion, six hundred eighty-eight million, six hundred seventy-one thousand, six hundred eighty-seven".