43681901 has 2 divisors, whose sum is σ = 43681902. Its totient is φ = 43681900.

The previous prime is 43681879. The next prime is 43681903. The reversal of 43681901 is 10918634.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28079401 + 15602500 = 5299^2 + 3950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43681901 is a prime.

Together with 43681903, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43681903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21840950 + 21840951.

It is an arithmetic number, because the mean of its divisors is an integer number (21840951).

Almost surely, 2^43681901 is an apocalyptic number.

It is an amenable number.

43681901 is a deficient number, since it is larger than the sum of its proper divisors (1).

43681901 is an equidigital number, since it uses as much as digits as its factorization.

43681901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 43681901 is about 6609.2284723710. The cubic root of 43681901 is about 352.1820172832.

The spelling of 43681901 in words is "forty-three million, six hundred eighty-one thousand, nine hundred one".