646027720649 has 2 divisors, whose sum is σ = 646027720650. Its totient is φ = 646027720648.

The previous prime is 646027720627. The next prime is 646027720669. The reversal of 646027720649 is 946027720646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 413761557049 + 232266163600 = 643243^2 + 481940^2 .

It is a cyclic number.

It is not a de Polignac number, because 646027720649 - 2²⁴ = 646010943433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 646027720649.

It is not a weakly prime, because it can be changed into another prime (646027720609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323013860324 + 323013860325.

It is an arithmetic number, because the mean of its divisors is an integer number (323013860325).

Almost surely, 2^646027720649 is an apocalyptic number.

It is an amenable number.

646027720649 is a deficient number, since it is larger than the sum of its proper divisors (1).

646027720649 is an equidigital number, since it uses as much as digits as its factorization.

646027720649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6096384, while the sum is 53.

The spelling of 646027720649 in words is "six hundred forty-six billion, twenty-seven million, seven hundred twenty thousand, six hundred forty-nine".