998521366242877 has 4 divisors (see below), whose sum is σ = 998521430744860. Its totient is φ = 998521301740896.

The previous prime is 998521366242839. The next prime is 998521366242887. The reversal of 998521366242877 is 778242663125899.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 49767649235161 + 948753717007716 = 7054619^2 + 30801846^2 .

It is a 3-Lehmer number, since φ(998521366242877) divides (998521366242877-1)³.

It is a cyclic number.

It is not a de Polignac number, because 998521366242877 - 2⁷ = 998521366242749 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 998521366242797 and 998521366242806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998521366242887) 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, 6450199 + ... + 45151387.

It is an arithmetic number, because the mean of its divisors is an integer number (249630357686215).

It is a Poulet number, since it divides 2^{998521366242876}-1.

Almost surely, 2^{998521366242877} is an apocalyptic number.

998521366242877 is the 25800793-rd pentagonal number.

It is an amenable number.

998521366242877 is a deficient number, since it is larger than the sum of its proper divisors (64501983).

998521366242877 is a wasteful number, since it uses less digits than its factorization.

998521366242877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64501982.

The product of its digits is 4389396480, while the sum is 79.

The spelling of 998521366242877 in words is "nine hundred ninety-eight trillion, five hundred twenty-one billion, three hundred sixty-six million, two hundred forty-two thousand, eight hundred seventy-seven".