646917407 has 2 divisors, whose sum is σ = 646917408. Its totient is φ = 646917406.

The previous prime is 646917391. The next prime is 646917409. The reversal of 646917407 is 704719646.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 646917407 - 2⁴ = 646917391 is a prime.

Together with 646917409, 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 (646917409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323458703 + 323458704.

It is an arithmetic number, because the mean of its divisors is an integer number (323458704).

Almost surely, 2^646917407 is an apocalyptic number.

646917407 is a deficient number, since it is larger than the sum of its proper divisors (1).

646917407 is an equidigital number, since it uses as much as digits as its factorization.

646917407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 44.

The square root of 646917407 is about 25434.5710991949. The cubic root of 646917407 is about 864.8675694662.

The spelling of 646917407 in words is "six hundred forty-six million, nine hundred seventeen thousand, four hundred seven".