646378133 has 2 divisors, whose sum is σ = 646378134. Its totient is φ = 646378132.

The previous prime is 646378127. The next prime is 646378151. The reversal of 646378133 is 331873646.

646378133 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 347710609 + 298667524 = 18647^2 + 17282^2 .

It is a cyclic number.

It is not a de Polignac number, because 646378133 - 2¹⁸ = 646115989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646378433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323189066 + 323189067.

It is an arithmetic number, because the mean of its divisors is an integer number (323189067).

Almost surely, 2^646378133 is an apocalyptic number.

It is an amenable number.

646378133 is a deficient number, since it is larger than the sum of its proper divisors (1).

646378133 is an equidigital number, since it uses as much as digits as its factorization.

646378133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 41.

The square root of 646378133 is about 25423.9676879908. The cubic root of 646378133 is about 864.6271831631.

The spelling of 646378133 in words is "six hundred forty-six million, three hundred seventy-eight thousand, one hundred thirty-three".