646510651 has 2 divisors, whose sum is σ = 646510652. Its totient is φ = 646510650.

The previous prime is 646510639. The next prime is 646510679. The reversal of 646510651 is 156015646.

It is a happy number.

646510651 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 is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646510651 is a prime.

It is not a weakly prime, because it can be changed into another prime (646510691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323255325 + 323255326.

It is an arithmetic number, because the mean of its divisors is an integer number (323255326).

Almost surely, 2^646510651 is an apocalyptic number.

646510651 is a deficient number, since it is larger than the sum of its proper divisors (1).

646510651 is an equidigital number, since it uses as much as digits as its factorization.

646510651 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 646510651 is about 25426.5737172746. The cubic root of 646510651 is about 864.6862666571.

The spelling of 646510651 in words is "six hundred forty-six million, five hundred ten thousand, six hundred fifty-one".