660399 has 16 divisors (see below), whose sum is σ = 974592. Its totient is φ = 395648.

The previous prime is 660391. The next prime is 660403. The reversal of 660399 is 993066.

It is a cyclic number.

It is not a de Polignac number, because 660399 - 2³ = 660391 is a prime.

It is a super-2 number, since 2×660399² = 872253678402, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660391) 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 15 ways as a sum of consecutive naturals, for example, 892 + ... + 1454.

It is an arithmetic number, because the mean of its divisors is an integer number (60912).

2⁶⁶⁰³⁹⁹ is an apocalyptic number.

660399 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

660399 is a deficient number, since it is larger than the sum of its proper divisors (314193).

660399 is a wasteful number, since it uses less digits than its factorization.

660399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 606.

The product of its (nonzero) digits is 8748, while the sum is 33.

The square root of 660399 is about 812.6493708851. The cubic root of 660399 is about 87.0834184707.

The spelling of 660399 in words is "six hundred sixty thousand, three hundred ninety-nine".