681465409 has 2 divisors, whose sum is σ = 681465410. Its totient is φ = 681465408.

The previous prime is 681465401. The next prime is 681465443. The reversal of 681465409 is 904564186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 550934784 + 130530625 = 23472^2 + 11425^2 .

It is a cyclic number.

It is not a de Polignac number, because 681465409 - 2³ = 681465401 is a prime.

It is not a weakly prime, because it can be changed into another prime (681465401) 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, 340732704 + 340732705.

It is an arithmetic number, because the mean of its divisors is an integer number (340732705).

Almost surely, 2^681465409 is an apocalyptic number.

It is an amenable number.

681465409 is a deficient number, since it is larger than the sum of its proper divisors (1).

681465409 is an equidigital number, since it uses as much as digits as its factorization.

681465409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 207360, while the sum is 43.

The square root of 681465409 is about 26104.8924341779. The cubic root of 681465409 is about 879.9971629557.

The spelling of 681465409 in words is "six hundred eighty-one million, four hundred sixty-five thousand, four hundred nine".