998861 has 2 divisors, whose sum is σ = 998862. Its totient is φ = 998860.

The previous prime is 998857. The next prime is 998897. The reversal of 998861 is 168899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 990025 + 8836 = 995^2 + 94^2 .

It is an emirp because it is prime and its reverse (168899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 998861 - 2² = 998857 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499430 + 499431.

It is an arithmetic number, because the mean of its divisors is an integer number (499431).

2⁹⁹⁸⁸⁶¹ is an apocalyptic number.

It is an amenable number.

998861 is a deficient number, since it is larger than the sum of its proper divisors (1).

998861 is an equidigital number, since it uses as much as digits as its factorization.

998861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 41.

The square root of 998861 is about 999.4303377425. The cubic root of 998861 is about 99.9620189095.

The spelling of 998861 in words is "nine hundred ninety-eight thousand, eight hundred sixty-one".