161906789 has 4 divisors (see below), whose sum is σ = 176625600. Its totient is φ = 147187980.

The previous prime is 161906761. The next prime is 161906803. The reversal of 161906789 is 987609161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 161906789 - 2²⁰ = 160858213 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161906389) 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 in 3 ways as a sum of consecutive naturals, for example, 7359389 + ... + 7359410.

It is an arithmetic number, because the mean of its divisors is an integer number (44156400).

Almost surely, 2^161906789 is an apocalyptic number.

It is an amenable number.

161906789 is a deficient number, since it is larger than the sum of its proper divisors (14718811).

161906789 is a wasteful number, since it uses less digits than its factorization.

161906789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14718810.

The product of its (nonzero) digits is 163296, while the sum is 47.

The square root of 161906789 is about 12724.2598605970. The cubic root of 161906789 is about 545.0316049343.

The spelling of 161906789 in words is "one hundred sixty-one million, nine hundred six thousand, seven hundred eighty-nine".