43681004217581 has 2 divisors, whose sum is σ = 43681004217582. Its totient is φ = 43681004217580.

The previous prime is 43681004217439. The next prime is 43681004217589. The reversal of 43681004217581 is 18571240018634.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43671413149225 + 9591068356 = 6608435^2 + 97934^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-43681004217581 is a prime.

It is a super-2 number, since 2×43681004217581² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (43681004217589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21840502108790 + 21840502108791.

It is an arithmetic number, because the mean of its divisors is an integer number (21840502108791).

Almost surely, 2^{43681004217581} is an apocalyptic number.

It is an amenable number.

43681004217581 is a deficient number, since it is larger than the sum of its proper divisors (1).

43681004217581 is an equidigital number, since it uses as much as digits as its factorization.

43681004217581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1290240, while the sum is 50.

The spelling of 43681004217581 in words is "forty-three trillion, six hundred eighty-one billion, four million, two hundred seventeen thousand, five hundred eighty-one".