9999978 has 48 divisors (see below), whose sum is σ = 21809280.
Its totient is φ = 3055104.
The previous prime is 9999973. The next prime is 9999991. The reversal of 9999978 is 8799999.
It is not an unprimeable number, because it can be changed into a prime (9999971) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (11) of ones.
It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 126543 + ... + 126621.
It is an arithmetic number, because the mean of its divisors is an integer number (454360).
Almost surely, 29999978 is an apocalyptic number.
9999978 is an abundant number, since it is smaller than the sum of its proper divisors (11809302).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9999978 is a wasteful number, since it uses less digits than its factorization.
9999978 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 191 (or 174 counting only the distinct ones).
The product of its digits is 3306744, while the sum is 60.
The square root of 9999978 is about 3162.2741816610.
The cubic root of 9999978 is about 215.4433110112.
The spelling of 9999978 in words is "nine million, nine hundred ninety-nine thousand, nine hundred seventy-eight".