643775051 has 2 divisors, whose sum is σ = 643775052. Its totient is φ = 643775050.

The previous prime is 643775021. The next prime is 643775053. The reversal of 643775051 is 150577346.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 643775051 - 2¹⁴ = 643758667 is a prime.

Together with 643775053, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 643774996 and 643775014.

It is not a weakly prime, because it can be changed into another prime (643775053) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321887525 + 321887526.

It is an arithmetic number, because the mean of its divisors is an integer number (321887526).

Almost surely, 2^643775051 is an apocalyptic number.

643775051 is a deficient number, since it is larger than the sum of its proper divisors (1).

643775051 is an equidigital number, since it uses as much as digits as its factorization.

643775051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 88200, while the sum is 38.

The square root of 643775051 is about 25372.7225776029. The cubic root of 643775051 is about 863.4649514189.

The spelling of 643775051 in words is "six hundred forty-three million, seven hundred seventy-five thousand, fifty-one".