643541197801 has 2 divisors, whose sum is σ = 643541197802. Its totient is φ = 643541197800.

The previous prime is 643541197777. The next prime is 643541197847. The reversal of 643541197801 is 108791145346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 544202765401 + 99338432400 = 737701^2 + 315180^2 .

It is a cyclic number.

It is not a de Polignac number, because 643541197801 - 2¹⁹ = 643540673513 is a prime.

It is not a weakly prime, because it can be changed into another prime (643541197891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321770598900 + 321770598901.

It is an arithmetic number, because the mean of its divisors is an integer number (321770598901).

Almost surely, 2^643541197801 is an apocalyptic number.

It is an amenable number.

643541197801 is a deficient number, since it is larger than the sum of its proper divisors (1).

643541197801 is an equidigital number, since it uses as much as digits as its factorization.

643541197801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 725760, while the sum is 49.

The spelling of 643541197801 in words is "six hundred forty-three billion, five hundred forty-one million, one hundred ninety-seven thousand, eight hundred one".