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681409 is a prime number
BaseRepresentation
bin10100110010111000001
31021121201101
42212113001
5133301114
622334401
75535421
oct2462701
91247641
10681409
11425a53
1228a401
131ab201
1413a481
15d6d74
hexa65c1

681409 has 2 divisors, whose sum is σ = 681410. Its totient is φ = 681408.

The previous prime is 681407. The next prime is 681419. The reversal of 681409 is 904186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680625 + 784 = 825^2 + 28^2 .

It is a cyclic number.

It is not a de Polignac number, because 681409 - 21 = 681407 is a prime.

Together with 681407, it forms a pair of twin primes.

681409 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (681403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340704 + 340705.

It is an arithmetic number, because the mean of its divisors is an integer number (340705).

2681409 is an apocalyptic number.

It is an amenable number.

681409 is a deficient number, since it is larger than the sum of its proper divisors (1).

681409 is an equidigital number, since it uses as much as digits as its factorization.

681409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 681409 is about 825.4750147642. The cubic root of 681409 is about 87.9972881396.

The spelling of 681409 in words is "six hundred eighty-one thousand, four hundred nine".