2171189156491 has 2 divisors, whose sum is σ = 2171189156492. Its totient is φ = 2171189156490.

The previous prime is 2171189156467. The next prime is 2171189156531. The reversal of 2171189156491 is 1946519811712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2171189156491 - 2⁵ = 2171189156459 is a prime.

It is not a weakly prime, because it can be changed into another prime (2171189166491) 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, 1085594578245 + 1085594578246.

It is an arithmetic number, because the mean of its divisors is an integer number (1085594578246).

Almost surely, 2^{2171189156491} is an apocalyptic number.

2171189156491 is a deficient number, since it is larger than the sum of its proper divisors (1).

2171189156491 is an equidigital number, since it uses as much as digits as its factorization.

2171189156491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1088640, while the sum is 55.

The spelling of 2171189156491 in words is "two trillion, one hundred seventy-one billion, one hundred eighty-nine million, one hundred fifty-six thousand, four hundred ninety-one".