647686747 has 2 divisors, whose sum is σ = 647686748. Its totient is φ = 647686746.

The previous prime is 647686673. The next prime is 647686771. The reversal of 647686747 is 747686746.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647686747 is a prime.

It is not a weakly prime, because it can be changed into another prime (647686547) 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 as a sum of consecutive naturals, namely, 323843373 + 323843374.

It is an arithmetic number, because the mean of its divisors is an integer number (323843374).

Almost surely, 2^647686747 is an apocalyptic number.

647686747 is a deficient number, since it is larger than the sum of its proper divisors (1).

647686747 is an equidigital number, since it uses as much as digits as its factorization.

647686747 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9483264, while the sum is 55.

The square root of 647686747 is about 25449.6905089237. The cubic root of 647686747 is about 865.2102786583.

Subtracting 647686747 from its reverse (747686746), we obtain a palindrome (99999999).

The spelling of 647686747 in words is "six hundred forty-seven million, six hundred eighty-six thousand, seven hundred forty-seven".