999917665541 has 4 divisors (see below), whose sum is σ = 999937032300. Its totient is φ = 999898298784.

The previous prime is 999917665517. The next prime is 999917665589. The reversal of 999917665541 is 145566719999.

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 798252902500 + 201664763041 = 893450^2 + 449071^2 .

It is a cyclic number.

It is not a de Polignac number, because 999917665541 - 2¹⁰ = 999917664517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999917665501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9605726 + ... + 9709263.

It is an arithmetic number, because the mean of its divisors is an integer number (249984258075).

Almost surely, 2^999917665541 is an apocalyptic number.

It is an amenable number.

999917665541 is a deficient number, since it is larger than the sum of its proper divisors (19366759).

999917665541 is a wasteful number, since it uses less digits than its factorization.

999917665541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19366758.

The product of its digits is 165337200, while the sum is 71.

The spelling of 999917665541 in words is "nine hundred ninety-nine billion, nine hundred seventeen million, six hundred sixty-five thousand, five hundred forty-one".