161443591 has 2 divisors, whose sum is σ = 161443592. Its totient is φ = 161443590.

The previous prime is 161443573. The next prime is 161443621. The reversal of 161443591 is 195344161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161443591 - 2⁵ = 161443559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161443511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80721795 + 80721796.

It is an arithmetic number, because the mean of its divisors is an integer number (80721796).

Almost surely, 2^161443591 is an apocalyptic number.

161443591 is a deficient number, since it is larger than the sum of its proper divisors (1).

161443591 is an equidigital number, since it uses as much as digits as its factorization.

161443591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 161443591 is about 12706.0454508868. The cubic root of 161443591 is about 544.5113494514.

The spelling of 161443591 in words is "one hundred sixty-one million, four hundred forty-three thousand, five hundred ninety-one".