643129 has 2 divisors, whose sum is σ = 643130. Its totient is φ = 643128.

The previous prime is 643121. The next prime is 643183. The reversal of 643129 is 921346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 393129 + 250000 = 627^2 + 500^2 .

It is a cyclic number.

It is not a de Polignac number, because 643129 - 2³ = 643121 is a prime.

It is a super-2 number, since 2×643129² = 827229821282, which contains 22 as substring.

It is a nialpdrome in base 15.

It is not a weakly prime, because it can be changed into another prime (643121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321564 + 321565.

It is an arithmetic number, because the mean of its divisors is an integer number (321565).

2⁶⁴³¹²⁹ is an apocalyptic number.

It is an amenable number.

643129 is a deficient number, since it is larger than the sum of its proper divisors (1).

643129 is an equidigital number, since it uses as much as digits as its factorization.

643129 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 25.

The square root of 643129 is about 801.9532405321. The cubic root of 643129 is about 86.3176015554.

The spelling of 643129 in words is "six hundred forty-three thousand, one hundred twenty-nine".