998238776161 has 27 divisors (see below), whose sum is σ = 1116269719929. Its totient is φ = 892013443200.

The previous prime is 998238776149. The next prime is 998238776189. The reversal of 998238776161 is 161677832899.

The square root of 998238776161 is 999119.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 620677684561 + 377561091600 = 787831^2 + 614460^2 .

It is not a de Polignac number, because 998238776161 - 2⁷ = 998238776033 is a prime.

It is a super-2 number, since 2×998238776161² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (998238776141) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 670408105 + ... + 670409593.

Almost surely, 2^998238776161 is an apocalyptic number.

998238776161 is the 999119-th square number.

998238776161 is the 499560-th centered octagonal number.

It is an amenable number.

998238776161 is a deficient number, since it is larger than the sum of its proper divisors (118030943768).

998238776161 is an frugal number, since it uses more digits than its factorization.

998238776161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3122 (or 1561 counting only the distinct ones).

The product of its digits is 54867456, while the sum is 67.

The spelling of 998238776161 in words is "nine hundred ninety-eight billion, two hundred thirty-eight million, seven hundred seventy-six thousand, one hundred sixty-one".