161778738 has 32 divisors (see below), whose sum is σ = 353986560. Its totient is φ = 48882960.

The previous prime is 161778713. The next prime is 161778751. The reversal of 161778738 is 837877161.

It is a Curzon number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 20883 + ... + 27561.

It is an arithmetic number, because the mean of its divisors is an integer number (11062080).

Almost surely, 2^161778738 is an apocalyptic number.

161778738 is an abundant number, since it is smaller than the sum of its proper divisors (192207822).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161778738 is a wasteful number, since it uses less digits than its factorization.

161778738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7062.

The product of its digits is 395136, while the sum is 48.

The square root of 161778738 is about 12719.2270991598. The cubic root of 161778738 is about 544.8878797496.

The spelling of 161778738 in words is "one hundred sixty-one million, seven hundred seventy-eight thousand, seven hundred thirty-eight".