1685638 has 4 divisors (see below), whose sum is σ = 2528460. Its totient is φ = 842818.

The previous prime is 1685627. The next prime is 1685681. The reversal of 1685638 is 8365861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8365861 = 7 ⋅1195123.

It is a plaindrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 1685597 and 1685606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 421408 + ... + 421411.

It is an arithmetic number, because the mean of its divisors is an integer number (632115).

2^1685638 is an apocalyptic number.

1685638 is a deficient number, since it is larger than the sum of its proper divisors (842822).

1685638 is an equidigital number, since it uses as much as digits as its factorization.

1685638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842821.

The product of its digits is 34560, while the sum is 37.

The square root of 1685638 is about 1298.3212237347. The cubic root of 1685638 is about 119.0112740301.

The spelling of 1685638 in words is "one million, six hundred eighty-five thousand, six hundred thirty-eight".