161939919 has 4 divisors (see below), whose sum is σ = 215919896. Its totient is φ = 107959944.

The previous prime is 161939917. The next prime is 161939927. The reversal of 161939919 is 919939161.

161939919 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 919939161 = 3 ⋅306646387.

It is not a de Polignac number, because 161939919 - 2¹ = 161939917 is a prime.

It is a super-2 number, since 2×161939919² = 52449074731453122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161939917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26989984 + ... + 26989989.

It is an arithmetic number, because the mean of its divisors is an integer number (53979974).

Almost surely, 2^161939919 is an apocalyptic number.

161939919 is a deficient number, since it is larger than the sum of its proper divisors (53979977).

161939919 is an equidigital number, since it uses as much as digits as its factorization.

161939919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53979976.

The product of its digits is 118098, while the sum is 48.

The square root of 161939919 is about 12725.5616379003. The cubic root of 161939919 is about 545.0687778980.

The spelling of 161939919 in words is "one hundred sixty-one million, nine hundred thirty-nine thousand, nine hundred nineteen".