686059921 has 8 divisors (see below), whose sum is σ = 691353000. Its totient is φ = 680776320.

The previous prime is 686059903. The next prime is 686059963. The reversal of 686059921 is 129950686.

It can be written as a sum of positive squares in 4 ways, for example, as 929296 + 685130625 = 964^2 + 26175^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 3-Lehmer number, since φ(686059921) divides (686059921-1)³.

It is a cyclic number.

It is a Carmichael number.

It is not a de Polignac number, because 686059921 - 2⁵ = 686059889 is a prime.

It is a deceptive number, since it divides R_686059920.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686059721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 219115 + ... + 222223.

It is an arithmetic number, because the mean of its divisors is an integer number (86419125).

It is a Poulet number, since it divides 2^686059920-1.

Almost surely, 2^686059921 is an apocalyptic number.

It is an amenable number.

686059921 is a deficient number, since it is larger than the sum of its proper divisors (5293079).

686059921 is a wasteful number, since it uses less digits than its factorization.

686059921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4739.

The product of its (nonzero) digits is 233280, while the sum is 46.

The square root of 686059921 is about 26192.7455796448. The cubic root of 686059921 is about 881.9704129982.

The spelling of 686059921 in words is "six hundred eighty-six million, fifty-nine thousand, nine hundred twenty-one".