647006861 has 2 divisors, whose sum is σ = 647006862. Its totient is φ = 647006860.

The previous prime is 647006839. The next prime is 647006863. The reversal of 647006861 is 168600746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 636805225 + 10201636 = 25235^2 + 3194^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647006861 is a prime.

Together with 647006863, 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 (647006863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323503430 + 323503431.

It is an arithmetic number, because the mean of its divisors is an integer number (323503431).

Almost surely, 2^647006861 is an apocalyptic number.

It is an amenable number.

647006861 is a deficient number, since it is larger than the sum of its proper divisors (1).

647006861 is an equidigital number, since it uses as much as digits as its factorization.

647006861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48384, while the sum is 38.

The square root of 647006861 is about 25436.3295504678. The cubic root of 647006861 is about 864.9074314831.

The spelling of 647006861 in words is "six hundred forty-seven million, six thousand, eight hundred sixty-one".