999389947 has 4 divisors (see below), whose sum is σ = 999497016. Its totient is φ = 999282880.

The previous prime is 999389939. The next prime is 999389971. The reversal of 999389947 is 749983999.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 749983999 = 7159 ⋅104761.

It is a cyclic number.

It is not a de Polignac number, because 999389947 - 2³ = 999389939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999389917) 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, 38038 + ... + 58699.

It is an arithmetic number, because the mean of its divisors is an integer number (249874254).

Almost surely, 2^999389947 is an apocalyptic number.

999389947 is a deficient number, since it is larger than the sum of its proper divisors (107069).

999389947 is a wasteful number, since it uses less digits than its factorization.

999389947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107068.

The product of its digits is 39680928, while the sum is 67.

The square root of 999389947 is about 31613.1293452578. The cubic root of 999389947 is about 999.7966076344.

The spelling of 999389947 in words is "nine hundred ninety-nine million, three hundred eighty-nine thousand, nine hundred forty-seven".