643451033 has 2 divisors, whose sum is σ = 643451034. Its totient is φ = 643451032.

The previous prime is 643451021. The next prime is 643451047. The reversal of 643451033 is 330154346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 454030864 + 189420169 = 21308^2 + 13763^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643451033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643450987 and 643451005.

It is not a weakly prime, because it can be changed into another prime (643451063) 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, 321725516 + 321725517.

It is an arithmetic number, because the mean of its divisors is an integer number (321725517).

Almost surely, 2^643451033 is an apocalyptic number.

It is an amenable number.

643451033 is a deficient number, since it is larger than the sum of its proper divisors (1).

643451033 is an equidigital number, since it uses as much as digits as its factorization.

643451033 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 29.

The square root of 643451033 is about 25366.3366097669. The cubic root of 643451033 is about 863.3200637817.

The spelling of 643451033 in words is "six hundred forty-three million, four hundred fifty-one thousand, thirty-three".