686798505621 has 12 divisors (see below), whose sum is σ = 992415689772. Its totient is φ = 457693330176.

The previous prime is 686798505607. The next prime is 686798505629. The reversal of 686798505621 is 126505897686.

686798505621 is a `hidden beast` number, since 6 + 8 + 67 + 9 + 8 + 5 + 0 + 562 + 1 = 666.

686798505621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 507386960721 + 179411544900 = 712311^2 + 423570^2 .

It is not a de Polignac number, because 686798505621 - 2¹⁰ = 686798504597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686798505629) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14336446 + ... + 14384271.

It is an arithmetic number, because the mean of its divisors is an integer number (82701307481).

Almost surely, 2^686798505621 is an apocalyptic number.

It is an amenable number.

686798505621 is a deficient number, since it is larger than the sum of its proper divisors (305617184151).

686798505621 is a wasteful number, since it uses less digits than its factorization.

686798505621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28723380 (or 28723377 counting only the distinct ones).

The product of its (nonzero) digits is 43545600, while the sum is 63.

The spelling of 686798505621 in words is "six hundred eighty-six billion, seven hundred ninety-eight million, five hundred five thousand, six hundred twenty-one".