647705739971 has 2 divisors, whose sum is σ = 647705739972. Its totient is φ = 647705739970.

The previous prime is 647705739929. The next prime is 647705739973. The reversal of 647705739971 is 179937507746.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647705739971 is a prime.

Together with 647705739973, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 647705739898 and 647705739907.

It is not a weakly prime, because it can be changed into another prime (647705739973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323852869985 + 323852869986.

It is an arithmetic number, because the mean of its divisors is an integer number (323852869986).

Almost surely, 2^647705739971 is an apocalyptic number.

647705739971 is a deficient number, since it is larger than the sum of its proper divisors (1).

647705739971 is an equidigital number, since it uses as much as digits as its factorization.

647705739971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70013160, while the sum is 65.

The spelling of 647705739971 in words is "six hundred forty-seven billion, seven hundred five million, seven hundred thirty-nine thousand, nine hundred seventy-one".