999648391 has 16 divisors (see below), whose sum is σ = 1170400000. Its totient is φ = 835930368.

The previous prime is 999648367. The next prime is 999648401. The reversal of 999648391 is 193846999.

It is not a de Polignac number, because 999648391 - 2⁹ = 999647879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999648191) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 374620 + ... + 377278.

It is an arithmetic number, because the mean of its divisors is an integer number (73150000).

Almost surely, 2^999648391 is an apocalyptic number.

999648391 is a deficient number, since it is larger than the sum of its proper divisors (170751609).

999648391 is a wasteful number, since it uses less digits than its factorization.

999648391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3958.

The product of its digits is 3779136, while the sum is 58.

The square root of 999648391 is about 31617.2166864827. The cubic root of 999648391 is about 999.8827832608.

The spelling of 999648391 in words is "nine hundred ninety-nine million, six hundred forty-eight thousand, three hundred ninety-one".