999999000020 has 12 divisors (see below), whose sum is σ = 2099997900084. Its totient is φ = 399999600000.

The previous prime is 999999000001. The next prime is 999999000053. The reversal of 999999000020 is 20000999999.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 630077163076 + 369921836944 = 793774^2 + 608212^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 999999000020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24999974981 + ... + 24999975020.

It is an arithmetic number, because the mean of its divisors is an integer number (174999825007).

Almost surely, 2^999999000020 is an apocalyptic number.

It is an amenable number.

999999000020 is an abundant number, since it is smaller than the sum of its proper divisors (1099998900064).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999999000020 is a wasteful number, since it uses less digits than its factorization.

999999000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49999950010 (or 49999950008 counting only the distinct ones).

The product of its (nonzero) digits is 1062882, while the sum is 56.

It can be divided in two parts, 99999 and 9000020, that added together give a palindrome (9100019).

The spelling of 999999000020 in words is "nine hundred ninety-nine billion, nine hundred ninety-nine million, twenty", and thus it is an aban number.