998531 has 4 divisors (see below), whose sum is σ = 1001832. Its totient is φ = 995232.

The previous prime is 998527. The next prime is 998537. The reversal of 998531 is 135899.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 998531 - 2² = 998527 is a prime.

It is a super-2 number, since 2×998531² = 1994128315922, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 998491 and 998500.

It is not an unprimeable number, because it can be changed into a prime (998537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1145 + ... + 1818.

It is an arithmetic number, because the mean of its divisors is an integer number (250458).

2⁹⁹⁸⁵³¹ is an apocalyptic number.

998531 is a deficient number, since it is larger than the sum of its proper divisors (3301).

998531 is a wasteful number, since it uses less digits than its factorization.

998531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3300.

The product of its digits is 9720, while the sum is 35.

The square root of 998531 is about 999.2652300566. The cubic root of 998531 is about 99.9510093364.

The spelling of 998531 in words is "nine hundred ninety-eight thousand, five hundred thirty-one".