161720878 has 16 divisors (see below), whose sum is σ = 273760560. Its totient is φ = 70974400.

The previous prime is 161720869. The next prime is 161720879. The reversal of 161720878 is 878027161.

161720878 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 161720878.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161720879) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 126103 + ... + 127378.

It is an arithmetic number, because the mean of its divisors is an integer number (17110035).

Almost surely, 2^161720878 is an apocalyptic number.

161720878 is a deficient number, since it is larger than the sum of its proper divisors (112039682).

161720878 is a wasteful number, since it uses less digits than its factorization.

161720878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253523.

The product of its (nonzero) digits is 37632, while the sum is 40.

The square root of 161720878 is about 12716.9523864800. The cubic root of 161720878 is about 544.8229124731.

The spelling of 161720878 in words is "one hundred sixty-one million, seven hundred twenty thousand, eight hundred seventy-eight".