161955851 has 2 divisors, whose sum is σ = 161955852. Its totient is φ = 161955850.

The previous prime is 161955839. The next prime is 161955869. The reversal of 161955851 is 158559161.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161955851 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 161955799 and 161955808.

It is not a weakly prime, because it can be changed into another prime (161955251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80977925 + 80977926.

It is an arithmetic number, because the mean of its divisors is an integer number (80977926).

Almost surely, 2^161955851 is an apocalyptic number.

161955851 is a deficient number, since it is larger than the sum of its proper divisors (1).

161955851 is an equidigital number, since it uses as much as digits as its factorization.

161955851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54000, while the sum is 41.

The square root of 161955851 is about 12726.1876066637. The cubic root of 161955851 is about 545.0866523275.

The spelling of 161955851 in words is "one hundred sixty-one million, nine hundred fifty-five thousand, eight hundred fifty-one".