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685991 is a prime number
BaseRepresentation
bin10100111011110100111
31021212000002
42213132213
5133422431
622411515
75554655
oct2473647
91255002
10685991
11429439
12290b9b
131b0317
1413bdd5
15d83cb
hexa77a7

685991 has 2 divisors, whose sum is σ = 685992. Its totient is φ = 685990.

The previous prime is 685987. The next prime is 686003. The reversal of 685991 is 199586.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 685991 - 22 = 685987 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685591) 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 as a sum of consecutive naturals, namely, 342995 + 342996.

It is an arithmetic number, because the mean of its divisors is an integer number (342996).

2685991 is an apocalyptic number.

685991 is a deficient number, since it is larger than the sum of its proper divisors (1).

685991 is an equidigital number, since it uses as much as digits as its factorization.

685991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 38.

The square root of 685991 is about 828.2457364816. The cubic root of 685991 is about 88.1940878008.

The spelling of 685991 in words is "six hundred eighty-five thousand, nine hundred ninety-one".