1688421 has 32 divisors (see below), whose sum is σ = 2757888. Its totient is φ = 898560.

The previous prime is 1688413. The next prime is 1688443. The reversal of 1688421 is 1248861.

It is not a de Polignac number, because 1688421 - 2³ = 1688413 is a prime.

It is a Curzon number.

1688421 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688411) 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 31 ways as a sum of consecutive naturals, for example, 31831 + ... + 31883.

It is an arithmetic number, because the mean of its divisors is an integer number (86184).

2^1688421 is an apocalyptic number.

It is an amenable number.

1688421 is a deficient number, since it is larger than the sum of its proper divisors (1069467).

1688421 is a wasteful number, since it uses less digits than its factorization.

1688421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141.

The product of its digits is 3072, while the sum is 30.

The square root of 1688421 is about 1299.3925503865. The cubic root of 1688421 is about 119.0767341639.

The spelling of 1688421 in words is "one million, six hundred eighty-eight thousand, four hundred twenty-one".