161906243 has 2 divisors, whose sum is σ = 161906244. Its totient is φ = 161906242.

The previous prime is 161906179. The next prime is 161906267. The reversal of 161906243 is 342609161.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161906243 - 2⁶ = 161906179 is a prime.

It is not a weakly prime, because it can be changed into another prime (161906293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80953121 + 80953122.

It is an arithmetic number, because the mean of its divisors is an integer number (80953122).

Almost surely, 2^161906243 is an apocalyptic number.

161906243 is a deficient number, since it is larger than the sum of its proper divisors (1).

161906243 is an equidigital number, since it uses as much as digits as its factorization.

161906243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 161906243 is about 12724.2384055000. The cubic root of 161906243 is about 545.0309922616.

The spelling of 161906243 in words is "one hundred sixty-one million, nine hundred six thousand, two hundred forty-three".