643547101 has 2 divisors, whose sum is σ = 643547102. Its totient is φ = 643547100.

The previous prime is 643546999. The next prime is 643547117. The reversal of 643547101 is 101745346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 583174201 + 60372900 = 24149^2 + 7770^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643547101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643547131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321773550 + 321773551.

It is an arithmetic number, because the mean of its divisors is an integer number (321773551).

Almost surely, 2^643547101 is an apocalyptic number.

It is an amenable number.

643547101 is a deficient number, since it is larger than the sum of its proper divisors (1).

643547101 is an equidigital number, since it uses as much as digits as its factorization.

643547101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 643547101 is about 25368.2301511162. The cubic root of 643547101 is about 863.3630265457.

The spelling of 643547101 in words is "six hundred forty-three million, five hundred forty-seven thousand, one hundred one".