645779227 has 2 divisors, whose sum is σ = 645779228. Its totient is φ = 645779226.

The previous prime is 645779219. The next prime is 645779269. The reversal of 645779227 is 722977546.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645779227 - 2³ = 645779219 is a prime.

It is not a weakly prime, because it can be changed into another prime (645779287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322889613 + 322889614.

It is an arithmetic number, because the mean of its divisors is an integer number (322889614).

Almost surely, 2^645779227 is an apocalyptic number.

645779227 is a deficient number, since it is larger than the sum of its proper divisors (1).

645779227 is an equidigital number, since it uses as much as digits as its factorization.

645779227 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1481760, while the sum is 49.

The square root of 645779227 is about 25412.1865843929. The cubic root of 645779227 is about 864.3600586030.

The spelling of 645779227 in words is "six hundred forty-five million, seven hundred seventy-nine thousand, two hundred twenty-seven".