1664587 has 4 divisors (see below), whose sum is σ = 1671736. Its totient is φ = 1657440.

The previous prime is 1664569. The next prime is 1664627. The reversal of 1664587 is 7854661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7854661 = 23 ⋅341507.

It is a cyclic number.

It is not a de Polignac number, because 1664587 - 2⁷ = 1664459 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1664557) 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, 3213 + ... + 3694.

It is an arithmetic number, because the mean of its divisors is an integer number (417934).

2^1664587 is an apocalyptic number.

1664587 is a deficient number, since it is larger than the sum of its proper divisors (7149).

1664587 is an equidigital number, since it uses as much as digits as its factorization.

1664587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7148.

The product of its digits is 40320, while the sum is 37.

The square root of 1664587 is about 1290.1887458818. The cubic root of 1664587 is about 118.5137752743.

It can be divided in two parts, 166 and 4587, that added together give a triangular number (4753 = T₉₇).

The spelling of 1664587 in words is "one million, six hundred sixty-four thousand, five hundred eighty-seven".