161783978 has 16 divisors (see below), whose sum is σ = 261398016. Its totient is φ = 74878320.

The previous prime is 161783977. The next prime is 161783989. The reversal of 161783978 is 879387161.

161783978 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161783971) 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 7 ways as a sum of consecutive naturals, for example, 55301 + ... + 58152.

It is an arithmetic number, because the mean of its divisors is an integer number (16337376).

Almost surely, 2^161783978 is an apocalyptic number.

161783978 is a deficient number, since it is larger than the sum of its proper divisors (99614038).

161783978 is a wasteful number, since it uses less digits than its factorization.

161783978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113509.

The product of its digits is 508032, while the sum is 50.

The square root of 161783978 is about 12719.4330848509. The cubic root of 161783978 is about 544.8937626440.

The spelling of 161783978 in words is "one hundred sixty-one million, seven hundred eighty-three thousand, nine hundred seventy-eight".