686522951705889 has 63 divisors (see below), whose sum is σ = 1055075668583209. Its totient is φ = 446500127839680.

The previous prime is 686522951705881. The next prime is 686522951705893. The reversal of 686522951705889 is 988507159225686.

The square root of 686522951705889 is 26201583.

It is a perfect power (a square), and thus also a powerful number.

686522951705889 is a `hidden beast` number, since 6 + 8 + 6 + 5 + 2 + 29 + 5 + 1 + 7 + 0 + 588 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 300822418358289 + 385700533347600 = 17344233^2 + 19639260^2 .

It is not a de Polignac number, because 686522951705889 - 2³ = 686522951705881 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686522951705881) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 29005140547 + ... + 29005164215.

Almost surely, 2^{686522951705889} is an apocalyptic number.

686522951705889 is the 26201583-rd square number.

686522951705889 is the 13100792-nd centered octagonal number.

It is an amenable number.

686522951705889 is a deficient number, since it is larger than the sum of its proper divisors (368552716877320).

686522951705889 is an frugal number, since it uses more digits than its factorization.

686522951705889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47438 (or 23713 counting only the distinct ones).

The product of its (nonzero) digits is 5225472000, while the sum is 81.

686522951705889 divided by its sum of digits (81) gives a square (8475591996369 = 2911287²).

The spelling of 686522951705889 in words is "six hundred eighty-six trillion, five hundred twenty-two billion, nine hundred fifty-one million, seven hundred five thousand, eight hundred eighty-nine".