646934251 has 2 divisors, whose sum is σ = 646934252. Its totient is φ = 646934250.

The previous prime is 646934243. The next prime is 646934261. The reversal of 646934251 is 152439646.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 646934251 - 2³ = 646934243 is a prime.

It is not a weakly prime, because it can be changed into another prime (646934261) 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, 323467125 + 323467126.

It is an arithmetic number, because the mean of its divisors is an integer number (323467126).

Almost surely, 2^646934251 is an apocalyptic number.

646934251 is a deficient number, since it is larger than the sum of its proper divisors (1).

646934251 is an equidigital number, since it uses as much as digits as its factorization.

646934251 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 40.

The square root of 646934251 is about 25434.9022211606. The cubic root of 646934251 is about 864.8750756810.

The spelling of 646934251 in words is "six hundred forty-six million, nine hundred thirty-four thousand, two hundred fifty-one".