999718019881 has 9 divisors (see below), whose sum is σ = 1162945430199. Its totient is φ = 856895160744.

The previous prime is 999718019857. The next prime is 999718020011. The reversal of 999718019881 is 188910817999.

The square root of 999718019881 is 999859.

It is a perfect power (a square), and thus also a powerful number.

999718019881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 265755715225 + 733962304656 = 515515^2 + 856716^2 .

It is not a de Polignac number, because 999718019881 - 2⁷ = 999718019753 is a prime.

It is a super-2 number, since 2×999718019881² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 999718019881.

It is not an unprimeable number, because it can be changed into a prime (999718019851) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6927595 + ... + 7070431.

It is an arithmetic number, because the mean of its divisors is an integer number (129216158911).

Almost surely, 2^999718019881 is an apocalyptic number.

999718019881 is the 999859-th square number.

999718019881 is the 499930-th centered octagonal number.

It is an amenable number.

999718019881 is a deficient number, since it is larger than the sum of its proper divisors (163227410318).

999718019881 is an frugal number, since it uses more digits than its factorization.

999718019881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285688 (or 142844 counting only the distinct ones).

The product of its (nonzero) digits is 23514624, while the sum is 70.

The spelling of 999718019881 in words is "nine hundred ninety-nine billion, seven hundred eighteen million, nineteen thousand, eight hundred eighty-one".