999660 has 24 divisors (see below), whose sum is σ = 2799216. Its totient is φ = 266560.

The previous prime is 999653. The next prime is 999667. The reversal of 999660 is 66999.

999660 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (999653) and next prime (999667).

It is a nialpdrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 999660.

It is not an unprimeable number, because it can be changed into a prime (999667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8271 + ... + 8390.

It is an arithmetic number, because the mean of its divisors is an integer number (116634).

2⁹⁹⁹⁶⁶⁰ is an apocalyptic number.

It is an amenable number.

999660 is an abundant number, since it is smaller than the sum of its proper divisors (1799556).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999660 is a wasteful number, since it uses less digits than its factorization.

999660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16673 (or 16671 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 999660 is about 999.8299855475. The cubic root of 999660 is about 99.9886653820.

The spelling of 999660 in words is "nine hundred ninety-nine thousand, six hundred sixty".