99381391 has 4 divisors (see below), whose sum is σ = 99748384. Its totient is φ = 99014400.

The previous prime is 99381379. The next prime is 99381421. The reversal of 99381391 is 19318399.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19318399 = 547 ⋅35317.

It is a cyclic number.

It is not a de Polignac number, because 99381391 - 2¹³ = 99373199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99381341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 183090 + ... + 183631.

It is an arithmetic number, because the mean of its divisors is an integer number (24937096).

Almost surely, 2^99381391 is an apocalyptic number.

99381391 is a deficient number, since it is larger than the sum of its proper divisors (366993).

99381391 is a wasteful number, since it uses less digits than its factorization.

99381391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 366992.

The product of its digits is 52488, while the sum is 43.

The square root of 99381391 is about 9969.0215668339. The cubic root of 99381391 is about 463.1997934197.

The spelling of 99381391 in words is "ninety-nine million, three hundred eighty-one thousand, three hundred ninety-one".