51691 has 2 divisors, whose sum is σ = 51692. Its totient is φ = 51690.

The previous prime is 51683. The next prime is 51713. The reversal of 51691 is 19615.

It is an a-pointer prime, because the next prime (51713) can be obtained adding 51691 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51691 - 2³ = 51683 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25845 + 25846.

It is an arithmetic number, because the mean of its divisors is an integer number (25846).

2⁵¹⁶⁹¹ is an apocalyptic number.

51691 is a deficient number, since it is larger than the sum of its proper divisors (1).

51691 is an equidigital number, since it uses as much as digits as its factorization.

51691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 270, while the sum is 22.

The square root of 51691 is about 227.3565481793. The cubic root of 51691 is about 37.2510322072.

The spelling of 51691 in words is "fifty-one thousand, six hundred ninety-one".