687561461 has 2 divisors, whose sum is σ = 687561462. Its totient is φ = 687561460.

The previous prime is 687561451. The next prime is 687561463. The reversal of 687561461 is 164165786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 644855236 + 42706225 = 25394^2 + 6535^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687561461 is a prime.

Together with 687561463, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (687561463) 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, 343780730 + 343780731.

It is an arithmetic number, because the mean of its divisors is an integer number (343780731).

Almost surely, 2^687561461 is an apocalyptic number.

It is an amenable number.

687561461 is a deficient number, since it is larger than the sum of its proper divisors (1).

687561461 is an equidigital number, since it uses as much as digits as its factorization.

687561461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 44.

The square root of 687561461 is about 26221.3931933450. The cubic root of 687561461 is about 882.6133835010.

The spelling of 687561461 in words is "six hundred eighty-seven million, five hundred sixty-one thousand, four hundred sixty-one".