99381 has 8 divisors (see below), whose sum is σ = 133984. Its totient is φ = 65520.

The previous prime is 99377. The next prime is 99391. The reversal of 99381 is 18399.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 99381 - 2² = 99377 is a prime.

It is a super-3 number, since 3×99381³ = 2944634133370023, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

99381 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 366 + ... + 576.

It is an arithmetic number, because the mean of its divisors is an integer number (16748).

2⁹⁹³⁸¹ is an apocalyptic number.

It is an amenable number.

99381 is a deficient number, since it is larger than the sum of its proper divisors (34603).

99381 is a wasteful number, since it uses less digits than its factorization.

99381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371.

The product of its digits is 1944, while the sum is 30.

The square root of 99381 is about 315.2475217983. The cubic root of 99381 is about 46.3199185957.

The spelling of 99381 in words is "ninety-nine thousand, three hundred eighty-one".