161778668 has 6 divisors (see below), whose sum is σ = 283112676. Its totient is φ = 80889332.

The previous prime is 161778667. The next prime is 161778671. The reversal of 161778668 is 866877161.

161778668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (161778667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20222330 + ... + 20222337.

It is an arithmetic number, because the mean of its divisors is an integer number (47185446).

Almost surely, 2^161778668 is an apocalyptic number.

It is an amenable number.

161778668 is a deficient number, since it is larger than the sum of its proper divisors (121334008).

161778668 is a wasteful number, since it uses less digits than its factorization.

161778668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40444671 (or 40444669 counting only the distinct ones).

The product of its digits is 677376, while the sum is 50.

The square root of 161778668 is about 12719.2243474199. The cubic root of 161778668 is about 544.8878011605.

The spelling of 161778668 in words is "one hundred sixty-one million, seven hundred seventy-eight thousand, six hundred sixty-eight".