999666555444111 has 32 divisors (see below), whose sum is σ = 1394756226053568. Its totient is φ = 636190980572160.

The previous prime is 999666555444103. The next prime is 999666555444143. The reversal of 999666555444111 is 111444555666999.

It is not a de Polignac number, because 999666555444111 - 2³ = 999666555444103 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 (999666555444311) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 580598451 + ... + 582317691.

It is an arithmetic number, because the mean of its divisors is an integer number (43586132064174).

Almost surely, 2^{999666555444111} is an apocalyptic number.

999666555444111 is a deficient number, since it is larger than the sum of its proper divisors (395089670609457).

999666555444111 is a wasteful number, since it uses less digits than its factorization.

999666555444111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1818171.

The product of its digits is 1259712000, while the sum is 75.

The spelling of 999666555444111 in words is "nine hundred ninety-nine trillion, six hundred sixty-six billion, five hundred fifty-five million, four hundred forty-four thousand, one hundred eleven".