99991539 has 6 divisors (see below), whose sum is σ = 144432236. Its totient is φ = 66661020.

The previous prime is 99991519. The next prime is 99991559. The reversal of 99991539 is 93519999.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (99991519) and next prime (99991559).

It is a de Polignac number, because none of the positive numbers 2^k-99991539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99991519) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5555077 + ... + 5555094.

Almost surely, 2^99991539 is an apocalyptic number.

99991539 is a deficient number, since it is larger than the sum of its proper divisors (44440697).

99991539 is a wasteful number, since it uses less digits than its factorization.

99991539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11110177 (or 11110174 counting only the distinct ones).

The product of its digits is 885735, while the sum is 54.

The square root of 99991539 is about 9999.5769410511. The cubic root of 99991539 is about 464.1457921643.

The spelling of 99991539 in words is "ninety-nine million, nine hundred ninety-one thousand, five hundred thirty-nine".