661585 has 8 divisors (see below), whose sum is σ = 798336. Its totient is φ = 526320.

The previous prime is 661553. The next prime is 661603. The reversal of 661585 is 585166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661585 - 2⁵ = 661553 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1320 + ... + 1750.

It is an arithmetic number, because the mean of its divisors is an integer number (99792).

2⁶⁶¹⁵⁸⁵ is an apocalyptic number.

It is an amenable number.

661585 is a deficient number, since it is larger than the sum of its proper divisors (136751).

661585 is a wasteful number, since it uses less digits than its factorization.

661585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 743.

The product of its digits is 7200, while the sum is 31.

The square root of 661585 is about 813.3787555623. The cubic root of 661585 is about 87.1355178677.

The spelling of 661585 in words is "six hundred sixty-one thousand, five hundred eighty-five".