9999531 has 20 divisors (see below), whose sum is σ = 15306984. Its totient is φ = 6501600.

The previous prime is 9999511. The next prime is 9999533. The reversal of 9999531 is 1359999.

It is not a de Polignac number, because 9999531 - 2¹¹ = 9997483 is a prime.

It is a super-2 number, since 2×9999531² = 199981240439922, which contains 22 as substring.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9999533) 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 19 ways as a sum of consecutive naturals, for example, 1816 + ... + 4826.

Almost surely, 2^9999531 is an apocalyptic number.

9999531 is a deficient number, since it is larger than the sum of its proper divisors (5307453).

9999531 is a wasteful number, since it uses less digits than its factorization.

9999531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3064 (or 3055 counting only the distinct ones).

The product of its digits is 98415, while the sum is 45.

The square root of 9999531 is about 3162.2035038878. The cubic root of 9999531 is about 215.4401008510.

The spelling of 9999531 in words is "nine million, nine hundred ninety-nine thousand, five hundred thirty-one".