99997915 has 4 divisors (see below), whose sum is σ = 119997504. Its totient is φ = 79998328.

The previous prime is 99997913. The next prime is 99997949. The reversal of 99997915 is 51979999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 51979999 = 17 ⋅3057647.

It is a cyclic number.

It is not a de Polignac number, because 99997915 - 2¹ = 99997913 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99997915.

It is not an unprimeable number, because it can be changed into a prime (99997913) 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, 9999787 + ... + 9999796.

It is an arithmetic number, because the mean of its divisors is an integer number (29999376).

Almost surely, 2^99997915 is an apocalyptic number.

99997915 is a deficient number, since it is larger than the sum of its proper divisors (19999589).

99997915 is a wasteful number, since it uses less digits than its factorization.

99997915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19999588.

The product of its digits is 2066715, while the sum is 58.

The square root of 99997915 is about 9999.8957494566. The cubic root of 99997915 is about 464.1556574346.

The spelling of 99997915 in words is "ninety-nine million, nine hundred ninety-seven thousand, nine hundred fifteen".