1690987 has 4 divisors (see below), whose sum is σ = 1697976. Its totient is φ = 1684000.

The previous prime is 1690967. The next prime is 1690993. The reversal of 1690987 is 7890961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7890961 = 13 ⋅606997.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1690987 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

1690987 is a lucky number.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (1690967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3118 + ... + 3619.

It is an arithmetic number, because the mean of its divisors is an integer number (424494).

2^1690987 is an apocalyptic number.

1690987 is a deficient number, since it is larger than the sum of its proper divisors (6989).

1690987 is an equidigital number, since it uses as much as digits as its factorization.

1690987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6988.

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

The square root of 1690987 is about 1300.3795599747. The cubic root of 1690987 is about 119.1370264413.

The spelling of 1690987 in words is "one million, six hundred ninety thousand, nine hundred eighty-seven".