99999997 has 4 divisors (see below), whose sum is σ = 100078396.
Its totient is φ = 99921600.
The previous prime is 99999989. The next prime is 100000007. The reversal of 99999997 is 79999999.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79999999 = 1709 ⋅46811.
It can be written as a sum of positive squares in 2 ways, for example, as 96412761 + 3587236 = 9819^2 + 1894^2
It is a cyclic number.
It is not a de Polignac number, because 99999997 - 23 = 99999989 is a prime.
It is a Duffinian number.
It is a nialpdrome in base 10.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (99993997) 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, 37254 + ... + 39847.
It is an arithmetic number, because the mean of its divisors is an integer number (25019599).
Almost surely, 299999997 is an apocalyptic number.
It is an amenable number.
99999997 is a deficient number, since it is larger than the sum of its proper divisors (78399).
99999997 is a wasteful number, since it uses less digits than its factorization.
99999997 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 78398.
The product of its digits is 33480783, while the sum is 70.
The square root of 99999997 is about 9999.9998500000.
Note that the first 3 decimals coincide.
The cubic root of 99999997 is about 464.1588787197.
The spelling of 99999997 in words is "ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-seven".