686438587 has 2 divisors, whose sum is σ = 686438588. Its totient is φ = 686438586.

The previous prime is 686438531. The next prime is 686438591. The reversal of 686438587 is 785834686.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686438587 is a prime.

It is not a weakly prime, because it can be changed into another prime (686438507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 343219293 + 343219294.

It is an arithmetic number, because the mean of its divisors is an integer number (343219294).

Almost surely, 2^686438587 is an apocalyptic number.

686438587 is a deficient number, since it is larger than the sum of its proper divisors (1).

686438587 is an equidigital number, since it uses as much as digits as its factorization.

686438587 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7741440, while the sum is 55.

The square root of 686438587 is about 26199.9730343373. The cubic root of 686438587 is about 882.1326489646.

It can be divided in two parts, 6864 and 38587, that added together give a triangular number (45451 = T₃₀₁).

The spelling of 686438587 in words is "six hundred eighty-six million, four hundred thirty-eight thousand, five hundred eighty-seven".