201781161616 has 20 divisors (see below), whose sum is σ = 393574837500. Its totient is φ = 100213461632.

The previous prime is 201781161613. The next prime is 201781161623. The reversal of 201781161616 is 616161187102.

It is a happy number.

201781161616 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 123327392400 + 78453769216 = 351180^2 + 280096^2 .

It is not an unprimeable number, because it can be changed into a prime (201781161613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42317491 + ... + 42322258.

It is an arithmetic number, because the mean of its divisors is an integer number (19678741875).

Almost surely, 2^201781161616 is an apocalyptic number.

It is an amenable number.

201781161616 is a deficient number, since it is larger than the sum of its proper divisors (191793675884).

201781161616 is a wasteful number, since it uses less digits than its factorization.

201781161616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84639906 (or 84639900 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 40.

The spelling of 201781161616 in words is "two hundred one billion, seven hundred eighty-one million, one hundred sixty-one thousand, six hundred sixteen".