1688631 has 16 divisors (see below), whose sum is σ = 2592768. Its totient is φ = 957600.

The previous prime is 1688629. The next prime is 1688651. The reversal of 1688631 is 1368861.

It is not a de Polignac number, because 1688631 - 2¹ = 1688629 is a prime.

It is a super-2 number, since 2×1688631² = 5702949308322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1688592 and 1688601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3801 + ... + 4221.

It is an arithmetic number, because the mean of its divisors is an integer number (162048).

2^1688631 is an apocalyptic number.

1688631 is a deficient number, since it is larger than the sum of its proper divisors (904137).

1688631 is a wasteful number, since it uses less digits than its factorization.

1688631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622.

The product of its digits is 6912, while the sum is 33.

The square root of 1688631 is about 1299.4733548634. The cubic root of 1688631 is about 119.0816707442.

The spelling of 1688631 in words is "one million, six hundred eighty-eight thousand, six hundred thirty-one".