660905 has 16 divisors (see below), whose sum is σ = 946944. Its totient is φ = 432960.

The previous prime is 660901. The next prime is 660917. The reversal of 660905 is 509066.

It is not a de Polignac number, because 660905 - 2² = 660901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660901) 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, 395 + ... + 1215.

It is an arithmetic number, because the mean of its divisors is an integer number (59184).

2⁶⁶⁰⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

660905 is a deficient number, since it is larger than the sum of its proper divisors (286039).

660905 is a wasteful number, since it uses less digits than its factorization.

660905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 660905 is about 812.9606386536. The cubic root of 660905 is about 87.1056539983.

The spelling of 660905 in words is "six hundred sixty thousand, nine hundred five".