646825969 has 2 divisors, whose sum is σ = 646825970. Its totient is φ = 646825968.

The previous prime is 646825951. The next prime is 646825999. The reversal of 646825969 is 969528646.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 548121744 + 98704225 = 23412^2 + 9935^2 .

It is a cyclic number.

It is not a de Polignac number, because 646825969 - 2⁷ = 646825841 is a prime.

It is a super-2 number, since 2×646825969² = 836767668345577922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (646825919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323412984 + 323412985.

It is an arithmetic number, because the mean of its divisors is an integer number (323412985).

Almost surely, 2^646825969 is an apocalyptic number.

It is an amenable number.

646825969 is a deficient number, since it is larger than the sum of its proper divisors (1).

646825969 is an equidigital number, since it uses as much as digits as its factorization.

646825969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5598720, while the sum is 55.

The square root of 646825969 is about 25432.7735215804. The cubic root of 646825969 is about 864.8268195518.

The spelling of 646825969 in words is "six hundred forty-six million, eight hundred twenty-five thousand, nine hundred sixty-nine".