161921943 has 16 divisors (see below), whose sum is σ = 244412640. Its totient is φ = 105910272.

The previous prime is 161921939. The next prime is 161921951. The reversal of 161921943 is 349129161.

It is a happy number.

It is not a de Polignac number, because 161921943 - 2² = 161921939 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161921898 and 161921907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161921843) 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 in 15 ways as a sum of consecutive naturals, for example, 55146 + ... + 58007.

It is an arithmetic number, because the mean of its divisors is an integer number (15275790).

Almost surely, 2^161921943 is an apocalyptic number.

161921943 is a deficient number, since it is larger than the sum of its proper divisors (82490697).

161921943 is a wasteful number, since it uses less digits than its factorization.

161921943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113215 (or 113209 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 161921943 is about 12724.8553233426. The cubic root of 161921943 is about 545.0486088564.

The spelling of 161921943 in words is "one hundred sixty-one million, nine hundred twenty-one thousand, nine hundred forty-three".