99391865 has 4 divisors (see below), whose sum is σ = 119270244. Its totient is φ = 79513488.

The previous prime is 99391861. The next prime is 99391871. The reversal of 99391865 is 56819399.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10523536 + 88868329 = 3244^2 + 9427^2 .

It is a cyclic number.

It is not a de Polignac number, because 99391865 - 2² = 99391861 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99391861) 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, 9939182 + ... + 9939191.

It is an arithmetic number, because the mean of its divisors is an integer number (29817561).

Almost surely, 2^99391865 is an apocalyptic number.

It is an amenable number.

99391865 is a deficient number, since it is larger than the sum of its proper divisors (19878379).

99391865 is a wasteful number, since it uses less digits than its factorization.

99391865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19878378.

The product of its digits is 524880, while the sum is 50.

The square root of 99391865 is about 9969.5468803753. The cubic root of 99391865 is about 463.2160653600.

The spelling of 99391865 in words is "ninety-nine million, three hundred ninety-one thousand, eight hundred sixty-five".