1688506 has 4 divisors (see below), whose sum is σ = 2532762. Its totient is φ = 844252.

The previous prime is 1688497. The next prime is 1688509. The reversal of 1688506 is 6058861.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6058861 = 37 ⋅163753.

It can be written as a sum of positive squares in only one way, i.e., 950625 + 737881 = 975^2 + 859^2 .

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1688509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 422125 + ... + 422128.

2^1688506 is an apocalyptic number.

1688506 is a deficient number, since it is larger than the sum of its proper divisors (844256).

1688506 is an equidigital number, since it uses as much as digits as its factorization.

1688506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844255.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 1688506 is about 1299.4252575658. The cubic root of 1688506 is about 119.0787323529.

The spelling of 1688506 in words is "one million, six hundred eighty-eight thousand, five hundred six".