998001001 has 4 divisors (see below), whose sum is σ = 998886100. Its totient is φ = 997115904.

The previous prime is 998000999. The next prime is 998001019. The reversal of 998001001 is 100100899.

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 338744025 + 659256976 = 18405^2 + 25676^2 .

It is a cyclic number.

It is not a de Polignac number, because 998001001 - 2¹ = 998000999 is a prime.

It is a Duffinian number.

998001001 is a modest number, since divided by 1001 gives 998 as remainder.

It is not an unprimeable number, because it can be changed into a prime (998001401) 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 3 ways as a sum of consecutive naturals, for example, 440856 + ... + 443113.

It is an arithmetic number, because the mean of its divisors is an integer number (249721525).

Almost surely, 2^998001001 is an apocalyptic number.

It is an amenable number.

998001001 is a deficient number, since it is larger than the sum of its proper divisors (885099).

998001001 is a wasteful number, since it uses less digits than its factorization.

998001001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 885098.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 998001001 is about 31591.1538409093. The cubic root of 998001001 is about 999.3332225066. Note that the first 3 decimals are identical.

The spelling of 998001001 in words is "nine hundred ninety-eight million, one thousand, one".