1688491 has 12 divisors (see below), whose sum is σ = 2080728. Its totient is φ = 1361472.

The previous prime is 1688471. The next prime is 1688497. The reversal of 1688491 is 1948861.

It is a happy number.

It is not a de Polignac number, because 1688491 - 2⁷ = 1688363 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1688491.

It is not an unprimeable number, because it can be changed into a prime (1688497) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 181 + ... + 1846.

It is an arithmetic number, because the mean of its divisors is an integer number (173394).

2^1688491 is an apocalyptic number.

1688491 is a deficient number, since it is larger than the sum of its proper divisors (392237).

1688491 is a wasteful number, since it uses less digits than its factorization.

1688491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2058 (or 2051 counting only the distinct ones).

The product of its digits is 13824, while the sum is 37.

The square root of 1688491 is about 1299.4194857705. The cubic root of 1688491 is about 119.0783797361.

The spelling of 1688491 in words is "one million, six hundred eighty-eight thousand, four hundred ninety-one".