999999999999001 has 4 divisors (see below), whose sum is σ = 1000021818385332. Its totient is φ = 999978181612672.

The previous prime is 999999999998939. The next prime is 999999999999043. The reversal of 999999999999001 is 100999999999999.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 756240320030976 + 243759679968025 = 27499824^2 + 15612805^2 .

It is a cyclic number.

It is not a de Polignac number, because 999999999999001 - 2⁴¹ = 997800976743449 is a prime.

It is a super-9 number, since 9×999999999999001⁹ (a number of 136 digits) contains 999999999 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 999999999999001.

It is not an unprimeable number, because it can be changed into a prime (999999999999071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10909124416 + ... + 10909216081.

It is an arithmetic number, because the mean of its divisors is an integer number (250005454596333).

Almost surely, 2^{999999999999001} is an apocalyptic number.

It is an amenable number.

999999999999001 is a deficient number, since it is larger than the sum of its proper divisors (21818386331).

999999999999001 is a wasteful number, since it uses less digits than its factorization.

999999999999001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21818386330.

The product of its (nonzero) digits is 282429536481, while the sum is 109.

It can be divided in two parts, 999999999 and 999001, that multiplied together give a palindrome (999000999000999).

The spelling of 999999999999001 in words is "nine hundred ninety-nine trillion, nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, one".