647383661 has 2 divisors, whose sum is σ = 647383662. Its totient is φ = 647383660.

The previous prime is 647383657. The next prime is 647383663. The reversal of 647383661 is 166383746.

647383661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 351750025 + 295633636 = 18755^2 + 17194^2 .

It is a cyclic number.

It is not a de Polignac number, because 647383661 - 2² = 647383657 is a prime.

Together with 647383663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647383663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323691830 + 323691831.

It is an arithmetic number, because the mean of its divisors is an integer number (323691831).

Almost surely, 2^647383661 is an apocalyptic number.

It is an amenable number.

647383661 is a deficient number, since it is larger than the sum of its proper divisors (1).

647383661 is an equidigital number, since it uses as much as digits as its factorization.

647383661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 44.

The square root of 647383661 is about 25443.7352014204. The cubic root of 647383661 is about 865.0752987787.

The spelling of 647383661 in words is "six hundred forty-seven million, three hundred eighty-three thousand, six hundred sixty-one".