646619797 has 2 divisors, whose sum is σ = 646619798. Its totient is φ = 646619796.

The previous prime is 646619783. The next prime is 646619801. The reversal of 646619797 is 797916646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 497022436 + 149597361 = 22294^2 + 12231^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646619797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646619737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323309898 + 323309899.

It is an arithmetic number, because the mean of its divisors is an integer number (323309899).

Almost surely, 2^646619797 is an apocalyptic number.

It is an amenable number.

646619797 is a deficient number, since it is larger than the sum of its proper divisors (1).

646619797 is an equidigital number, since it uses as much as digits as its factorization.

646619797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3429216, while the sum is 55.

The square root of 646619797 is about 25428.7199245263. The cubic root of 646619797 is about 864.7349236213.

The spelling of 646619797 in words is "six hundred forty-six million, six hundred nineteen thousand, seven hundred ninety-seven".