99999731 has 4 divisors (see below), whose sum is σ = 107692032. Its totient is φ = 92307432.

The previous prime is 99999721. The next prime is 99999773. The reversal of 99999731 is 13799999.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13799999 = 47 ⋅293617.

It is a cyclic number.

It is not a de Polignac number, because 99999731 - 2¹⁸ = 99737587 is a prime.

It is a super-2 number, since 2×99999731² = 19999892400144722, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (99999721) 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, 3846131 + ... + 3846156.

It is an arithmetic number, because the mean of its divisors is an integer number (26923008).

Almost surely, 2^99999731 is an apocalyptic number.

99999731 is a deficient number, since it is larger than the sum of its proper divisors (7692301).

99999731 is a wasteful number, since it uses less digits than its factorization.

99999731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7692300.

The product of its digits is 1240029, while the sum is 56.

The square root of 99999731 is about 9999.9865499910. The cubic root of 99999731 is about 464.1584671651.

The spelling of 99999731 in words is "ninety-nine million, nine hundred ninety-nine thousand, seven hundred thirty-one".