647891633 has 2 divisors, whose sum is σ = 647891634. Its totient is φ = 647891632.

The previous prime is 647891617. The next prime is 647891689. The reversal of 647891633 is 336198746.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 340660849 + 307230784 = 18457^2 + 17528^2 .

It is a cyclic number.

It is not a de Polignac number, because 647891633 - 2⁴ = 647891617 is a prime.

It is a super-2 number, since 2×647891633² = 839527136222813378, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (647891333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323945816 + 323945817.

It is an arithmetic number, because the mean of its divisors is an integer number (323945817).

Almost surely, 2^647891633 is an apocalyptic number.

It is an amenable number.

647891633 is a deficient number, since it is larger than the sum of its proper divisors (1).

647891633 is an equidigital number, since it uses as much as digits as its factorization.

647891633 is an evil number, because the sum of its binary digits is even.

The product of its digits is 653184, while the sum is 47.

The square root of 647891633 is about 25453.7155048138. The cubic root of 647891633 is about 865.3015011436.

The spelling of 647891633 in words is "six hundred forty-seven million, eight hundred ninety-one thousand, six hundred thirty-three".