643541029 has 2 divisors, whose sum is σ = 643541030. Its totient is φ = 643541028.

The previous prime is 643541023. The next prime is 643541047. The reversal of 643541029 is 920145346.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 355322500 + 288218529 = 18850^2 + 16977^2 .

It is a cyclic number.

It is not a de Polignac number, because 643541029 - 2⁷ = 643540901 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643540985 and 643541003.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643541023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321770514 + 321770515.

It is an arithmetic number, because the mean of its divisors is an integer number (321770515).

Almost surely, 2^643541029 is an apocalyptic number.

It is an amenable number.

643541029 is a deficient number, since it is larger than the sum of its proper divisors (1).

643541029 is an equidigital number, since it uses as much as digits as its factorization.

643541029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 643541029 is about 25368.1104735847. The cubic root of 643541029 is about 863.3603112010.

The spelling of 643541029 in words is "six hundred forty-three million, five hundred forty-one thousand, twenty-nine".