999666111 has 12 divisors (see below), whose sum is σ = 1369368456. Its totient is φ = 648216000.

The previous prime is 999666103. The next prime is 999666119. The reversal of 999666111 is 111666999.

It is an interprime number because it is at equal distance from previous prime (999666103) and next prime (999666119).

It is not a de Polignac number, because 999666111 - 2³ = 999666103 is a prime.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999666119) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 331611 + ... + 334611.

It is an arithmetic number, because the mean of its divisors is an integer number (114114038).

Almost surely, 2^999666111 is an apocalyptic number.

999666111 is a deficient number, since it is larger than the sum of its proper divisors (369702345).

999666111 is an frugal number, since it uses more digits than its factorization.

999666111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6042 (or 3041 counting only the distinct ones).

The product of its digits is 157464, while the sum is 48.

The square root of 999666111 is about 31617.4969123111. The cubic root of 999666111 is about 999.8886912775. Note that the first 3 decimals are identical.

The spelling of 999666111 in words is "nine hundred ninety-nine million, six hundred sixty-six thousand, one hundred eleven".