999999999999999 has 128 divisors (see below), whose sum is σ = 1614847741624320. Its totient is φ = 610154104320000.

The previous prime is 999999999999989. The next prime is 1000000000000037.

It is a happy number.

999999999999999 is nontrivially palindromic in base 10.

It is a Cunningham number, because it is equal to 10¹⁵-1.

It is a trimorphic number since its cube, 999999999999997000000000000002999999999999999, ends in 999999999999999.

It is not a de Polignac number, because 999999999999999 - 2¹⁵ = 999999999967231 is a prime.

It is a super-9 number, since 9×999999999999999⁹ (a number of 136 digits) contains 999999999 as substring.

It is a nude number because it is divisible by every one of its digits.

999999999999999 is a modest number, since divided by 99999999 gives 9999999 as remainder.

999999999999999 is a nontrivial repdigit in base 10.

It is a plaindrome in base 10.

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 (999999999999989) by changing a digit.

It is a Kaprekar number, because its square (999999999999998000000000000001) can be partitioned into two parts whose sum is 999999999999999.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 342643479 + ... + 345549639.

It is an arithmetic number, because the mean of its divisors is an integer number (12615997981440).

Almost surely, 2^{999999999999999} is an apocalyptic number.

999999999999999 is a deficient number, since it is larger than the sum of its proper divisors (614847741624321).

999999999999999 is a wasteful number, since it uses less digits than its factorization.

999999999999999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2906550 (or 2906544 counting only the distinct ones).

The product of its digits is 205891132094649, while the sum is 135.

The spelling of 999999999999999 in words is "nine hundred ninety-nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".