647668643 has 2 divisors, whose sum is σ = 647668644. Its totient is φ = 647668642.

The previous prime is 647668627. The next prime is 647668691. The reversal of 647668643 is 346866746.

647668643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647668643 - 2⁴ = 647668627 is a prime.

It is a super-2 number, since 2×647668643² = 838949342250922898, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 647668591 and 647668600.

It is not a weakly prime, because it can be changed into another prime (647668243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323834321 + 323834322.

It is an arithmetic number, because the mean of its divisors is an integer number (323834322).

Almost surely, 2^647668643 is an apocalyptic number.

647668643 is a deficient number, since it is larger than the sum of its proper divisors (1).

647668643 is an equidigital number, since it uses as much as digits as its factorization.

647668643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3483648, while the sum is 50.

The square root of 647668643 is about 25449.3348243132. The cubic root of 647668643 is about 865.2022171929.

The spelling of 647668643 in words is "six hundred forty-seven million, six hundred sixty-eight thousand, six hundred forty-three".