43651 has 2 divisors, whose sum is σ = 43652. Its totient is φ = 43650.

The previous prime is 43649. The next prime is 43661. The reversal of 43651 is 15634.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 43651 - 2¹ = 43649 is a prime.

Together with 43649, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (43661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21825 + 21826.

It is an arithmetic number, because the mean of its divisors is an integer number (21826).

2⁴³⁶⁵¹ is an apocalyptic number.

43651 is a deficient number, since it is larger than the sum of its proper divisors (1).

43651 is an equidigital number, since it uses as much as digits as its factorization.

43651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 360, while the sum is 19.

The square root of 43651 is about 208.9282173379. The cubic root of 43651 is about 35.2098952036.

It can be divided in two parts, 4 and 3651, that added together give a triangular number (3655 = T₈₅).

The spelling of 43651 in words is "forty-three thousand, six hundred fifty-one".