999990001 has 6 divisors (see below), whose sum is σ = 1021721330. Its totient is φ = 978711456.

The previous prime is 999989981. The next prime is 999990011. The reversal of 999990001 is 100099999.

It can be written as a sum of positive squares in only one way, i.e., 632271025 + 367718976 = 25145^2 + 19176^2 .

It is not a de Polignac number, because 999990001 - 2¹⁷ = 999858929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999990011) 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 5 ways as a sum of consecutive naturals, for example, 224136 + ... + 228553.

Almost surely, 2^999990001 is an apocalyptic number.

It is an amenable number.

999990001 is a deficient number, since it is larger than the sum of its proper divisors (21731329).

999990001 is an equidigital number, since it uses as much as digits as its factorization.

999990001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452783 (or 452736 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 46.

The square root of 999990001 is about 31622.6185032170. The cubic root of 999990001 is about 999.9966669889.

It can be divided in two parts, 9999 and 90001, that added together give a 5-th power (100000 = 10⁵).

The spelling of 999990001 in words is "nine hundred ninety-nine million, nine hundred ninety thousand, one".