998781181 has 2 divisors, whose sum is σ = 998781182. Its totient is φ = 998781180.

The previous prime is 998781169. The next prime is 998781241. The reversal of 998781181 is 181187899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 692216100 + 306565081 = 26310^2 + 17509^2 .

It is a cyclic number.

It is not a de Polignac number, because 998781181 - 2⁵ = 998781149 is a prime.

It is a super-2 number, since 2×998781181² = 1995127695039509522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998781481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499390590 + 499390591.

It is an arithmetic number, because the mean of its divisors is an integer number (499390591).

Almost surely, 2^998781181 is an apocalyptic number.

It is an amenable number.

998781181 is a deficient number, since it is larger than the sum of its proper divisors (1).

998781181 is an equidigital number, since it uses as much as digits as its factorization.

998781181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 52.

The square root of 998781181 is about 31603.4995055927. The cubic root of 998781181 is about 999.5935618304.

The spelling of 998781181 in words is "nine hundred ninety-eight million, seven hundred eighty-one thousand, one hundred eighty-one".