1687990 has 16 divisors (see below), whose sum is σ = 3090960. Its totient is φ = 663520.

The previous prime is 1687969. The next prime is 1687991. The reversal of 1687990 is 997861.

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 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, 841 + ... + 2020.

It is an arithmetic number, because the mean of its divisors is an integer number (193185).

2^1687990 is an apocalyptic number.

1687990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1687990 is a deficient number, since it is larger than the sum of its proper divisors (1402970).

1687990 is a wasteful number, since it uses less digits than its factorization.

1687990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2927.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 1687990 is about 1299.2266930755. The cubic root of 1687990 is about 119.0666011382.

The spelling of 1687990 in words is "one million, six hundred eighty-seven thousand, nine hundred ninety".