999998817 has 4 divisors (see below), whose sum is σ = 1333331760. Its totient is φ = 666665876.

The previous prime is 999998801. The next prime is 999998843. The reversal of 999998817 is 718899999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 999998817 - 2⁴ = 999998801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (999998017) 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, 166666467 + ... + 166666472.

It is an arithmetic number, because the mean of its divisors is an integer number (333332940).

Almost surely, 2^999998817 is an apocalyptic number.

It is an amenable number.

999998817 is a deficient number, since it is larger than the sum of its proper divisors (333332943).

999998817 is a wasteful number, since it uses less digits than its factorization.

999998817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333332942.

The product of its digits is 26453952, while the sum is 69.

The square root of 999998817 is about 31622.7578968059. The cubic root of 999998817 is about 999.9996056665. Note that the first 3 decimals are identical.

The spelling of 999998817 in words is "nine hundred ninety-nine million, nine hundred ninety-eight thousand, eight hundred seventeen".