1660987 has 4 divisors (see below), whose sum is σ = 1675800. Its totient is φ = 1646176.

The previous prime is 1660963. The next prime is 1661003. The reversal of 1660987 is 7890661.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1660987 - 2¹⁹ = 1136699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1660957) 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 3 ways as a sum of consecutive naturals, for example, 7237 + ... + 7462.

It is an arithmetic number, because the mean of its divisors is an integer number (418950).

2^1660987 is an apocalyptic number.

1660987 is a deficient number, since it is larger than the sum of its proper divisors (14813).

1660987 is a wasteful number, since it uses less digits than its factorization.

1660987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14812.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 1660987 is about 1288.7928460385. The cubic root of 1660987 is about 118.4282770832.

The spelling of 1660987 in words is "one million, six hundred sixty thousand, nine hundred eighty-seven".