99991331 has 16 divisors (see below), whose sum is σ = 116121600. Its totient is φ = 85092480.

The previous prime is 99991303. The next prime is 99991343. The reversal of 99991331 is 13319999.

It is not a de Polignac number, because 99991331 - 2¹⁰ = 99990307 is a prime.

It is a super-3 number, since 3×99991331³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99991831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35870 + ... + 38556.

It is an arithmetic number, because the mean of its divisors is an integer number (7257600).

Almost surely, 2^99991331 is an apocalyptic number.

99991331 is a deficient number, since it is larger than the sum of its proper divisors (16130269).

99991331 is a wasteful number, since it uses less digits than its factorization.

99991331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2914.

The product of its digits is 59049, while the sum is 44.

The square root of 99991331 is about 9999.5665406056. The cubic root of 99991331 is about 464.1454703291.

The spelling of 99991331 in words is "ninety-nine million, nine hundred ninety-one thousand, three hundred thirty-one".