643054021 has 2 divisors, whose sum is σ = 643054022. Its totient is φ = 643054020.

The previous prime is 643054001. The next prime is 643054081. The reversal of 643054021 is 120450346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 327103396 + 315950625 = 18086^2 + 17775^2 .

It is a cyclic number.

It is not a de Polignac number, because 643054021 - 2⁵ = 643053989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643054001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321527010 + 321527011.

It is an arithmetic number, because the mean of its divisors is an integer number (321527011).

Almost surely, 2^643054021 is an apocalyptic number.

It is an amenable number.

643054021 is a deficient number, since it is larger than the sum of its proper divisors (1).

643054021 is an equidigital number, since it uses as much as digits as its factorization.

643054021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 643054021 is about 25358.5098339788. The cubic root of 643054021 is about 863.1424698783.

The spelling of 643054021 in words is "six hundred forty-three million, fifty-four thousand, twenty-one".