648643129 has 2 divisors, whose sum is σ = 648643130. Its totient is φ = 648643128.

The previous prime is 648643081. The next prime is 648643139. The reversal of 648643129 is 921346846.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 545315904 + 103327225 = 23352^2 + 10165^2 .

It is a cyclic number.

It is not a de Polignac number, because 648643129 - 2²³ = 640254521 is a prime.

It is not a weakly prime, because it can be changed into another prime (648643139) 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, 324321564 + 324321565.

It is an arithmetic number, because the mean of its divisors is an integer number (324321565).

Almost surely, 2^648643129 is an apocalyptic number.

It is an amenable number.

648643129 is a deficient number, since it is larger than the sum of its proper divisors (1).

648643129 is an equidigital number, since it uses as much as digits as its factorization.

648643129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 248832, while the sum is 43.

The square root of 648643129 is about 25468.4732365330. The cubic root of 648643129 is about 865.6359291699.

The spelling of 648643129 in words is "six hundred forty-eight million, six hundred forty-three thousand, one hundred twenty-nine".