99981231 has 32 divisors (see below), whose sum is σ = 158822400. Its totient is φ = 54743040.

The previous prime is 99981229. The next prime is 99981251. The reversal of 99981231 is 13218999.

It is not a de Polignac number, because 99981231 - 2¹ = 99981229 is a prime.

It is a super-2 number, since 2×99981231² = 19992493104550722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99981221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70255 + ... + 71663.

It is an arithmetic number, because the mean of its divisors is an integer number (4963200).

Almost surely, 2^99981231 is an apocalyptic number.

99981231 is a deficient number, since it is larger than the sum of its proper divisors (58841169).

99981231 is a wasteful number, since it uses less digits than its factorization.

99981231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1559.

The product of its digits is 34992, while the sum is 42.

The square root of 99981231 is about 9999.0615059614. The cubic root of 99981231 is about 464.1298422174.

The spelling of 99981231 in words is "ninety-nine million, nine hundred eighty-one thousand, two hundred thirty-one".