646401061 has 2 divisors, whose sum is σ = 646401062. Its totient is φ = 646401060.

The previous prime is 646401043. The next prime is 646401101. The reversal of 646401061 is 160104646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 485364961 + 161036100 = 22031^2 + 12690^2 .

It is a cyclic number.

It is not a de Polignac number, because 646401061 - 2¹³ = 646392869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646401661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323200530 + 323200531.

It is an arithmetic number, because the mean of its divisors is an integer number (323200531).

Almost surely, 2^646401061 is an apocalyptic number.

It is an amenable number.

646401061 is a deficient number, since it is larger than the sum of its proper divisors (1).

646401061 is an equidigital number, since it uses as much as digits as its factorization.

646401061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 646401061 is about 25424.4185970889. The cubic root of 646401061 is about 864.6374062490.

The spelling of 646401061 in words is "six hundred forty-six million, four hundred one thousand, sixty-one".