686398905 has 12 divisors (see below), whose sum is σ = 1189758180. Its totient is φ = 366079392.

The previous prime is 686398859. The next prime is 686398927. The reversal of 686398905 is 509893686.

It can be written as a sum of positive squares in 2 ways, for example, as 327031056 + 359367849 = 18084^2 + 18957^2 .

It is not a de Polignac number, because 686398905 - 2⁷ = 686398777 is a prime.

It is a super-2 number, since 2×686398905² = 942286913570398050, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7626610 + ... + 7626699.

It is an arithmetic number, because the mean of its divisors is an integer number (99146515).

Almost surely, 2^686398905 is an apocalyptic number.

It is an amenable number.

686398905 is a deficient number, since it is larger than the sum of its proper divisors (503359275).

686398905 is a wasteful number, since it uses less digits than its factorization.

686398905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15253320 (or 15253317 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 54.

The square root of 686398905 is about 26199.2157325367. The cubic root of 686398905 is about 882.1156503755.

The spelling of 686398905 in words is "six hundred eighty-six million, three hundred ninety-eight thousand, nine hundred five".