161895421 has 2 divisors, whose sum is σ = 161895422. Its totient is φ = 161895420.

The previous prime is 161895389. The next prime is 161895427. The reversal of 161895421 is 124598161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 159896025 + 1999396 = 12645^2 + 1414^2 .

It is a cyclic number.

It is not a de Polignac number, because 161895421 - 2⁵ = 161895389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161895427) 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, 80947710 + 80947711.

It is an arithmetic number, because the mean of its divisors is an integer number (80947711).

Almost surely, 2^161895421 is an apocalyptic number.

It is an amenable number.

161895421 is a deficient number, since it is larger than the sum of its proper divisors (1).

161895421 is an equidigital number, since it uses as much as digits as its factorization.

161895421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 37.

The square root of 161895421 is about 12723.8131470090. The cubic root of 161895421 is about 545.0188484910.

The spelling of 161895421 in words is "one hundred sixty-one million, eight hundred ninety-five thousand, four hundred twenty-one".