1688428 has 24 divisors (see below), whose sum is σ = 3451392. Its totient is φ = 707664.

The previous prime is 1688413. The next prime is 1688443. The reversal of 1688428 is 8248861.

It is an interprime number because it is at equal distance from previous prime (1688413) and next prime (1688443).

It is a super-2 number, since 2×1688428² = 5701578222368, which contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 675 + ... + 1957.

It is an arithmetic number, because the mean of its divisors is an integer number (143808).

2^1688428 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1688428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1725696).

1688428 is an abundant number, since it is smaller than the sum of its proper divisors (1762964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1688428 is a wasteful number, since it uses less digits than its factorization.

1688428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1341 (or 1339 counting only the distinct ones).

The product of its digits is 24576, while the sum is 37.

The square root of 1688428 is about 1299.3952439500. The cubic root of 1688428 is about 119.0768987232.

It can be divided in two parts, 1688 and 428, that added together give a square (2116 = 46²).

The spelling of 1688428 in words is "one million, six hundred eighty-eight thousand, four hundred twenty-eight".