999999555 has 32 divisors (see below), whose sum is σ = 1671148800. Its totient is φ = 510106752.

The previous prime is 999999541. The next prime is 999999587. The reversal of 999999555 is 555999999.

999999555 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 999999555 - 2⁶ = 999999491 is a prime.

It is a super-2 number, since 2×999999555² = 1999998220000396050, which contains 22 as substring.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 999999555.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17476 + ... + 48014.

It is an arithmetic number, because the mean of its divisors is an integer number (52223400).

Almost surely, 2^999999555 is an apocalyptic number.

999999555 is a deficient number, since it is larger than the sum of its proper divisors (671149245).

999999555 is a wasteful number, since it uses less digits than its factorization.

999999555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30643.

The product of its digits is 66430125, while the sum is 69.

The square root of 999999555 is about 31622.7695656152. The cubic root of 999999555 is about 999.9998516666. Note that the first 3 decimals are identical.

The spelling of 999999555 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, five hundred fifty-five".