999997856 has 48 divisors (see below), whose sum is σ = 2312942688. Its totient is φ = 419577600.

The previous prime is 999997811. The next prime is 999997871. The reversal of 999997856 is 658799999.

It is a self number, because there is not a number n which added to its sum of digits gives 999997856.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104690 + ... + 113841.

It is an arithmetic number, because the mean of its divisors is an integer number (48186306).

Almost surely, 2^999997856 is an apocalyptic number.

It is an amenable number.

999997856 is an abundant number, since it is smaller than the sum of its proper divisors (1312944832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999997856 is a wasteful number, since it uses less digits than its factorization.

999997856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218565 (or 218557 counting only the distinct ones).

The product of its digits is 99202320, while the sum is 71.

The square root of 999997856 is about 31622.7427020491. The cubic root of 999997856 is about 999.9992853328. Note that the first 3 decimals are identical.

The spelling of 999997856 in words is "nine hundred ninety-nine million, nine hundred ninety-seven thousand, eight hundred fifty-six".