660840559 has 4 divisors (see below), whose sum is σ = 661298704. Its totient is φ = 660382416.

The previous prime is 660840553. The next prime is 660840589. The reversal of 660840559 is 955048066.

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 660840559 - 2⁷ = 660840431 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 (660840553) 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, 226902 + ... + 229795.

It is an arithmetic number, because the mean of its divisors is an integer number (165324676).

Almost surely, 2^660840559 is an apocalyptic number.

660840559 is a deficient number, since it is larger than the sum of its proper divisors (458145).

660840559 is a wasteful number, since it uses less digits than its factorization.

660840559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458144.

The product of its (nonzero) digits is 259200, while the sum is 43.

The square root of 660840559 is about 25706.8193092806. The cubic root of 660840559 is about 871.0282285112.

The spelling of 660840559 in words is "six hundred sixty million, eight hundred forty thousand, five hundred fifty-nine".