999999297867991 has 16 divisors (see below), whose sum is σ = 1032994627354624. Its totient is φ = 967471767075744.

The previous prime is 999999297867923. The next prime is 999999297868003. The reversal of 999999297867991 is 199768792999999.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 999999297867991 - 2³⁵ = 999964938129623 is a prime.

It is the 31622766-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999999297867091) by changing a digit.

It is a nontrivial repunit in base 31622765.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 146013351 + ... + 152708536.

It is an arithmetic number, because the mean of its divisors is an integer number (64562164209664).

Almost surely, 2^{999999297867991} is an apocalyptic number.

999999297867991 is a deficient number, since it is larger than the sum of its proper divisors (32995329486633).

999999297867991 is a wasteful number, since it uses less digits than its factorization.

999999297867991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298722670.

The product of its digits is 1822425980256, while the sum is 112.

The spelling of 999999297867991 in words is "nine hundred ninety-nine trillion, nine hundred ninety-nine billion, two hundred ninety-seven million, eight hundred sixty-seven thousand, nine hundred ninety-one".