646553629 has 2 divisors, whose sum is σ = 646553630. Its totient is φ = 646553628.

The previous prime is 646553623. The next prime is 646553659. The reversal of 646553629 is 926355646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 409455225 + 237098404 = 20235^2 + 15398^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646553629 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646553623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323276814 + 323276815.

It is an arithmetic number, because the mean of its divisors is an integer number (323276815).

Almost surely, 2^646553629 is an apocalyptic number.

It is an amenable number.

646553629 is a deficient number, since it is larger than the sum of its proper divisors (1).

646553629 is an equidigital number, since it uses as much as digits as its factorization.

646553629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1166400, while the sum is 46.

The square root of 646553629 is about 25427.4188426588. The cubic root of 646553629 is about 864.7054267761.

The spelling of 646553629 in words is "six hundred forty-six million, five hundred fifty-three thousand, six hundred twenty-nine".