643922105 has 4 divisors (see below), whose sum is σ = 772706532. Its totient is φ = 515137680.

The previous prime is 643922093. The next prime is 643922117. The reversal of 643922105 is 501229346.

It is a happy number.

643922105 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (643922093) and next prime (643922117).

It can be written as a sum of positive squares in 2 ways, for example, as 419881081 + 224041024 = 20491^2 + 14968^2 .

It is not a de Polignac number, because 643922105 - 2⁸ = 643921849 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64392206 + ... + 64392215.

It is an arithmetic number, because the mean of its divisors is an integer number (193176633).

Almost surely, 2^643922105 is an apocalyptic number.

It is an amenable number.

643922105 is a deficient number, since it is larger than the sum of its proper divisors (128784427).

643922105 is a wasteful number, since it uses less digits than its factorization.

643922105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128784426.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 643922105 is about 25375.6202879851. The cubic root of 643922105 is about 863.5306919328.

The spelling of 643922105 in words is "six hundred forty-three million, nine hundred twenty-two thousand, one hundred five".