999978000123 has 4 divisors (see below), whose sum is σ = 1333304000168. Its totient is φ = 666652000080.

The previous prime is 999978000113. The next prime is 999978000139. The reversal of 999978000123 is 321000879999.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 999978000123 - 2⁹ = 999977999611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999978000103) 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, 166663000018 + ... + 166663000023.

It is an arithmetic number, because the mean of its divisors is an integer number (333326000042).

Almost surely, 2^999978000123 is an apocalyptic number.

999978000123 is a deficient number, since it is larger than the sum of its proper divisors (333326000045).

999978000123 is a wasteful number, since it uses less digits than its factorization.

999978000123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333326000044.

The product of its (nonzero) digits is 2204496, while the sum is 57.

The spelling of 999978000123 in words is "nine hundred ninety-nine billion, nine hundred seventy-eight million, one hundred twenty-three", and thus it is an aban number.