647123843 has 4 divisors (see below), whose sum is σ = 650739240. Its totient is φ = 643508448.

The previous prime is 647123797. The next prime is 647123849. The reversal of 647123843 is 348321746.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 348321746 = 2 ⋅174160873.

It is a cyclic number.

It is not a de Polignac number, because 647123843 - 2²⁴ = 630346627 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 647123797 and 647123806.

It is not an unprimeable number, because it can be changed into a prime (647123849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1807430 + ... + 1807787.

It is an arithmetic number, because the mean of its divisors is an integer number (162684810).

Almost surely, 2^647123843 is an apocalyptic number.

647123843 is a deficient number, since it is larger than the sum of its proper divisors (3615397).

647123843 is a wasteful number, since it uses less digits than its factorization.

647123843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3615396.

The product of its digits is 96768, while the sum is 38.

The square root of 647123843 is about 25438.6289528347. The cubic root of 647123843 is about 864.9595548376.

The spelling of 647123843 in words is "six hundred forty-seven million, one hundred twenty-three thousand, eight hundred forty-three".