161099131591 has 2 divisors, whose sum is σ = 161099131592. Its totient is φ = 161099131590.

The previous prime is 161099131577. The next prime is 161099131651. The reversal of 161099131591 is 195131990161.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161099131591 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161099131511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80549565795 + 80549565796.

It is an arithmetic number, because the mean of its divisors is an integer number (80549565796).

Almost surely, 2^161099131591 is an apocalyptic number.

161099131591 is a deficient number, since it is larger than the sum of its proper divisors (1).

161099131591 is an equidigital number, since it uses as much as digits as its factorization.

161099131591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 65610, while the sum is 46.

The spelling of 161099131591 in words is "one hundred sixty-one billion, ninety-nine million, one hundred thirty-one thousand, five hundred ninety-one".