999915555 has 16 divisors (see below), whose sum is σ = 1603864224. Its totient is φ = 531955200.

The previous prime is 999915551. The next prime is 999915559. The reversal of 999915555 is 555519999.

It is an interprime number because it is at equal distance from previous prime (999915551) and next prime (999915559).

It is not a de Polignac number, because 999915555 - 2² = 999915551 is a prime.

It is a super-2 number, since 2×999915555² = 1999662234261916050, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 999915495 and 999915504.

It is not an unprimeable number, because it can be changed into a prime (999915551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77104 + ... + 89133.

It is an arithmetic number, because the mean of its divisors is an integer number (100241514).

Almost surely, 2^999915555 is an apocalyptic number.

999915555 is a deficient number, since it is larger than the sum of its proper divisors (603948669).

999915555 is a wasteful number, since it uses less digits than its factorization.

999915555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166646.

The product of its digits is 4100625, while the sum is 57.

The square root of 999915555 is about 31621.4413808100. The cubic root of 999915555 is about 999.9718508743.

The spelling of 999915555 in words is "nine hundred ninety-nine million, nine hundred fifteen thousand, five hundred fifty-five".