646458889 has 2 divisors, whose sum is σ = 646458890. Its totient is φ = 646458888.

The previous prime is 646458877. The next prime is 646458919. The reversal of 646458889 is 988854646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 479610000 + 166848889 = 21900^2 + 12917^2 .

It is a cyclic number.

It is not a de Polignac number, because 646458889 - 2⁹ = 646458377 is a prime.

It is a super-2 number, since 2×646458889² = 835818190334228642, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (646458859) 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, 323229444 + 323229445.

It is an arithmetic number, because the mean of its divisors is an integer number (323229445).

Almost surely, 2^646458889 is an apocalyptic number.

It is an amenable number.

646458889 is a deficient number, since it is larger than the sum of its proper divisors (1).

646458889 is an equidigital number, since it uses as much as digits as its factorization.

646458889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13271040, while the sum is 58.

The square root of 646458889 is about 25425.5558247996. Note that the first 3 decimals coincide. The cubic root of 646458889 is about 864.6631893962.

The spelling of 646458889 in words is "six hundred forty-six million, four hundred fifty-eight thousand, eight hundred eighty-nine".