999871893 has 30 divisors (see below), whose sum is σ = 1513710614. Its totient is φ = 635993424.

The previous prime is 999871883. The next prime is 999871963. The reversal of 999871893 is 398178999.

It can be written as a sum of positive squares in only one way, i.e., 909203409 + 90668484 = 30153^2 + 9522^2 .

It is not a de Polignac number, because 999871893 - 2⁴ = 999871877 is a prime.

It is a super-2 number, since 2×999871893² = 1999487604822806898, which contains 22 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 999871893.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999871853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 2518371 + ... + 2518767.

Almost surely, 2^999871893 is an apocalyptic number.

It is an amenable number.

999871893 is a deficient number, since it is larger than the sum of its proper divisors (513838721).

999871893 is an frugal number, since it uses more digits than its factorization.

999871893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495 (or 423 counting only the distinct ones).

The product of its digits is 8817984, while the sum is 63.

The square root of 999871893 is about 31620.7509872868. The cubic root of 999871893 is about 999.9572958430.

The spelling of 999871893 in words is "nine hundred ninety-nine million, eight hundred seventy-one thousand, eight hundred ninety-three".