646459973 has 2 divisors, whose sum is σ = 646459974. Its totient is φ = 646459972.

The previous prime is 646459951. The next prime is 646460051. The reversal of 646459973 is 379954646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 646328929 + 131044 = 25423^2 + 362^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646459973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646459943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323229986 + 323229987.

It is an arithmetic number, because the mean of its divisors is an integer number (323229987).

Almost surely, 2^646459973 is an apocalyptic number.

It is an amenable number.

646459973 is a deficient number, since it is larger than the sum of its proper divisors (1).

646459973 is an equidigital number, since it uses as much as digits as its factorization.

646459973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4898880, while the sum is 53.

The square root of 646459973 is about 25425.5771419254. The cubic root of 646459973 is about 864.6636726929.

The spelling of 646459973 in words is "six hundred forty-six million, four hundred fifty-nine thousand, nine hundred seventy-three".