99991517 has 2 divisors, whose sum is σ = 99991518. Its totient is φ = 99991516.

The previous prime is 99991499. The next prime is 99991519. The reversal of 99991517 is 71519999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73633561 + 26357956 = 8581^2 + 5134^2 .

It is a cyclic number.

It is not a de Polignac number, because 99991517 - 2¹⁰ = 99990493 is a prime.

It is a super-2 number, since 2×99991517² = 19996606943922578, which contains 22 as substring.

Together with 99991519, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99991519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49995758 + 49995759.

It is an arithmetic number, because the mean of its divisors is an integer number (49995759).

Almost surely, 2^99991517 is an apocalyptic number.

It is an amenable number.

99991517 is a deficient number, since it is larger than the sum of its proper divisors (1).

99991517 is an equidigital number, since it uses as much as digits as its factorization.

99991517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 229635, while the sum is 50.

The square root of 99991517 is about 9999.5758410045. The cubic root of 99991517 is about 464.1457581241.

The spelling of 99991517 in words is "ninety-nine million, nine hundred ninety-one thousand, five hundred seventeen".