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681691 = 798629
BaseRepresentation
bin10100110011011011011
31021122002211
42212123123
5133303231
622335551
75536303
oct2463333
91248084
10681691
1142618a
1228a5b7
131ab38a
1413a603
15d6eb1
hexa66db

681691 has 4 divisors (see below), whose sum is σ = 690400. Its totient is φ = 672984.

The previous prime is 681689. The next prime is 681719. The reversal of 681691 is 196186.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 681691 - 21 = 681689 is a prime.

It is a Duffinian number.

681691 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (681631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4236 + ... + 4393.

It is an arithmetic number, because the mean of its divisors is an integer number (172600).

2681691 is an apocalyptic number.

681691 is a deficient number, since it is larger than the sum of its proper divisors (8709).

681691 is an equidigital number, since it uses as much as digits as its factorization.

681691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8708.

The product of its digits is 2592, while the sum is 31.

The square root of 681691 is about 825.6458078377. The cubic root of 681691 is about 88.0094256433.

The spelling of 681691 in words is "six hundred eighty-one thousand, six hundred ninety-one".

Divisors: 1 79 8629 681691