647666653 has 2 divisors, whose sum is σ = 647666654. Its totient is φ = 647666652.

The previous prime is 647666651. The next prime is 647666687. The reversal of 647666653 is 356666746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 620906724 + 26759929 = 24918^2 + 5173^2 .

It is a cyclic number.

It is not a de Polignac number, because 647666653 - 2¹ = 647666651 is a prime.

Together with 647666651, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 647666597 and 647666606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647666651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323833326 + 323833327.

It is an arithmetic number, because the mean of its divisors is an integer number (323833327).

Almost surely, 2^647666653 is an apocalyptic number.

It is an amenable number.

647666653 is a deficient number, since it is larger than the sum of its proper divisors (1).

647666653 is an equidigital number, since it uses as much as digits as its factorization.

647666653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3265920, while the sum is 49.

The square root of 647666653 is about 25449.2957269941. The cubic root of 647666653 is about 865.2013310638.

The spelling of 647666653 in words is "six hundred forty-seven million, six hundred sixty-six thousand, six hundred fifty-three".