660091 has 4 divisors (see below), whose sum is σ = 662752. Its totient is φ = 657432.

The previous prime is 660073. The next prime is 660097. The reversal of 660091 is 190066.

660091 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 660091 - 2⁷ = 659963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (660097) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 915 + ... + 1468.

It is an arithmetic number, because the mean of its divisors is an integer number (165688).

2⁶⁶⁰⁰⁹¹ is an apocalyptic number.

660091 is a deficient number, since it is larger than the sum of its proper divisors (2661).

660091 is a wasteful number, since it uses less digits than its factorization.

660091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2660.

The product of its (nonzero) digits is 324, while the sum is 22.

The square root of 660091 is about 812.4598451616. The cubic root of 660091 is about 87.0698782404.

The spelling of 660091 in words is "six hundred sixty thousand, ninety-one".