998999020002121 has 4 divisors (see below), whose sum is σ = 998999241279172. Its totient is φ = 998998798725072.

The previous prime is 998999020002119. The next prime is 998999020002161. The reversal of 998999020002121 is 121200020999899.

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 286717650042121 + 712281369960000 = 16932739^2 + 26688600^2 .

It is a cyclic number.

It is not a de Polignac number, because 998999020002121 - 2¹ = 998999020002119 is a prime.

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 998999020002121.

It is not an unprimeable number, because it can be changed into a prime (998999020002161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103722366 + ... + 112943911.

It is an arithmetic number, because the mean of its divisors is an integer number (249749810319793).

Almost surely, 2^{998999020002121} is an apocalyptic number.

It is an amenable number.

998999020002121 is a deficient number, since it is larger than the sum of its proper divisors (221277051).

998999020002121 is a wasteful number, since it uses less digits than its factorization.

998999020002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221277050.

The product of its (nonzero) digits is 3779136, while the sum is 61.

The spelling of 998999020002121 in words is "nine hundred ninety-eight trillion, nine hundred ninety-nine billion, twenty million, two thousand, one hundred twenty-one".