687602681 has 2 divisors, whose sum is σ = 687602682. Its totient is φ = 687602680.

The previous prime is 687602659. The next prime is 687602683. The reversal of 687602681 is 186206786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 589275625 + 98327056 = 24275^2 + 9916^2 .

It is a cyclic number.

It is not a de Polignac number, because 687602681 - 2²⁶ = 620493817 is a prime.

It is a super-2 number, since 2×687602681² = 945594893836775522, which contains 22 as substring.

Together with 687602683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (687602683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343801340 + 343801341.

It is an arithmetic number, because the mean of its divisors is an integer number (343801341).

Almost surely, 2^687602681 is an apocalyptic number.

It is an amenable number.

687602681 is a deficient number, since it is larger than the sum of its proper divisors (1).

687602681 is an equidigital number, since it uses as much as digits as its factorization.

687602681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 44.

The square root of 687602681 is about 26222.1791809910. The cubic root of 687602681 is about 882.6310210015.

The spelling of 687602681 in words is "six hundred eighty-seven million, six hundred two thousand, six hundred eighty-one".