687489281 has 2 divisors, whose sum is σ = 687489282. Its totient is φ = 687489280.

The previous prime is 687489277. The next prime is 687489287. The reversal of 687489281 is 182984786.

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., 686911681 + 577600 = 26209^2 + 760^2 .

It is a cyclic number.

It is not a de Polignac number, because 687489281 - 2² = 687489277 is a prime.

It is a super-2 number, since 2×687489281² = 945283022979793922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (687489287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343744640 + 343744641.

It is an arithmetic number, because the mean of its divisors is an integer number (343744641).

Almost surely, 2^687489281 is an apocalyptic number.

It is an amenable number.

687489281 is a deficient number, since it is larger than the sum of its proper divisors (1).

687489281 is an equidigital number, since it uses as much as digits as its factorization.

687489281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1548288, while the sum is 53.

The square root of 687489281 is about 26220.0168001472. The cubic root of 687489281 is about 882.5824969224.

The spelling of 687489281 in words is "six hundred eighty-seven million, four hundred eighty-nine thousand, two hundred eighty-one".