998905 has 12 divisors (see below), whose sum is σ = 1255140. Its totient is φ = 762272.

The previous prime is 998897. The next prime is 998909. The reversal of 998905 is 509899.

It can be written as a sum of positive squares in 2 ways, for example, as 440896 + 558009 = 664^2 + 747^2 .

It is not a de Polignac number, because 998905 - 2³ = 998897 is a prime.

It is a super-2 number, since 2×998905² = 1995622398050, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11994 + ... + 12076.

It is an arithmetic number, because the mean of its divisors is an integer number (104595).

2⁹⁹⁸⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

998905 is a deficient number, since it is larger than the sum of its proper divisors (256235).

998905 is an equidigital number, since it uses as much as digits as its factorization.

998905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 40.

The square root of 998905 is about 999.4523500398. The cubic root of 998905 is about 99.9634866694.

The spelling of 998905 in words is "nine hundred ninety-eight thousand, nine hundred five".