43640506581491 has 2 divisors, whose sum is σ = 43640506581492. Its totient is φ = 43640506581490.

The previous prime is 43640506581439. The next prime is 43640506581499. The reversal of 43640506581491 is 19418560504634.

It is a happy number.

43640506581491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 43640506581491 - 2¹⁴ = 43640506565107 is a prime.

It is not a weakly prime, because it can be changed into another prime (43640506581499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21820253290745 + 21820253290746.

It is an arithmetic number, because the mean of its divisors is an integer number (21820253290746).

Almost surely, 2^{43640506581491} is an apocalyptic number.

43640506581491 is a deficient number, since it is larger than the sum of its proper divisors (1).

43640506581491 is an equidigital number, since it uses as much as digits as its factorization.

43640506581491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12441600, while the sum is 56.

The spelling of 43640506581491 in words is "forty-three trillion, six hundred forty billion, five hundred six million, five hundred eighty-one thousand, four hundred ninety-one".