43618868605561 has 2 divisors, whose sum is σ = 43618868605562. Its totient is φ = 43618868605560.

The previous prime is 43618868605511. The next prime is 43618868605589. The reversal of 43618868605561 is 16550686881634.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41355754552336 + 2263114053225 = 6430844^2 + 1504365^2 .

It is a cyclic number.

It is not a de Polignac number, because 43618868605561 - 2¹⁵ = 43618868572793 is a prime.

It is not a weakly prime, because it can be changed into another prime (43618868605511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21809434302780 + 21809434302781.

It is an arithmetic number, because the mean of its divisors is an integer number (21809434302781).

Almost surely, 2^{43618868605561} is an apocalyptic number.

It is an amenable number.

43618868605561 is a deficient number, since it is larger than the sum of its proper divisors (1).

43618868605561 is an equidigital number, since it uses as much as digits as its factorization.

43618868605561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 199065600, while the sum is 67.

The spelling of 43618868605561 in words is "forty-three trillion, six hundred eighteen billion, eight hundred sixty-eight million, six hundred five thousand, five hundred sixty-one".