1659987 has 16 divisors (see below), whose sum is σ = 2810880. Its totient is φ = 948456.

The previous prime is 1659971. The next prime is 1659997. The reversal of 1659987 is 7899561.

It is not a de Polignac number, because 1659987 - 2⁴ = 1659971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1659997) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4203 + ... + 4580.

It is an arithmetic number, because the mean of its divisors is an integer number (175680).

2^1659987 is an apocalyptic number.

1659987 is a deficient number, since it is larger than the sum of its proper divisors (1150893).

1659987 is an equidigital number, since it uses as much as digits as its factorization.

1659987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8799 (or 8793 counting only the distinct ones).

The product of its digits is 136080, while the sum is 45.

The square root of 1659987 is about 1288.4048276842. The cubic root of 1659987 is about 118.4045056646.

The spelling of 1659987 in words is "one million, six hundred fifty-nine thousand, nine hundred eighty-seven".