1687998 has 64 divisors (see below), whose sum is σ = 4112640. Its totient is φ = 456192.

The previous prime is 1687991. The next prime is 1687999. The reversal of 1687998 is 8997861.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 25161 + ... + 25227.

It is an arithmetic number, because the mean of its divisors is an integer number (64260).

2^1687998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1687998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2056320).

1687998 is an abundant number, since it is smaller than the sum of its proper divisors (2424642).

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

1687998 is a wasteful number, since it uses less digits than its factorization.

1687998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121.

The product of its digits is 217728, while the sum is 48.

The square root of 1687998 is about 1299.2297718264. The cubic root of 1687998 is about 119.0667892379.

The spelling of 1687998 in words is "one million, six hundred eighty-seven thousand, nine hundred ninety-eight".