999999655 has 4 divisors (see below), whose sum is σ = 1199999592. Its totient is φ = 799999720.

The previous prime is 999999613. The next prime is 999999667. The reversal of 999999655 is 556999999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 556999999 = 22669 ⋅24571.

It is not a de Polignac number, because 999999655 - 2⁷ = 999999527 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99999961 + ... + 99999970.

It is an arithmetic number, because the mean of its divisors is an integer number (299999898).

Almost surely, 2^999999655 is an apocalyptic number.

999999655 is a deficient number, since it is larger than the sum of its proper divisors (199999937).

999999655 is a wasteful number, since it uses less digits than its factorization.

999999655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199999936.

The product of its digits is 79716150, while the sum is 70.

The square root of 999999655 is about 31622.7711467544. The cubic root of 999999655 is about 999.9998850000. Note that the first 3 decimals are identical.

The spelling of 999999655 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, six hundred fifty-five".