161967391 has 2 divisors, whose sum is σ = 161967392. Its totient is φ = 161967390.

The previous prime is 161967373. The next prime is 161967413. The reversal of 161967391 is 193769161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161967391 - 2⁵ = 161967359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161967371) 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, 80983695 + 80983696.

It is an arithmetic number, because the mean of its divisors is an integer number (80983696).

Almost surely, 2^161967391 is an apocalyptic number.

161967391 is a deficient number, since it is larger than the sum of its proper divisors (1).

161967391 is an equidigital number, since it uses as much as digits as its factorization.

161967391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 43.

The square root of 161967391 is about 12726.6409943865. The cubic root of 161967391 is about 545.0995985523.

The spelling of 161967391 in words is "one hundred sixty-one million, nine hundred sixty-seven thousand, three hundred ninety-one".