261201153636 has 36 divisors (see below), whose sum is σ = 666795693564. Its totient is φ = 86205000000.

The previous prime is 261201153617. The next prime is 261201153667. The reversal of 261201153636 is 636351102162.

261201153636 is a `hidden beast` number, since 2 + 6 + 1 + 2 + 0 + 1 + 15 + 3 + 636 = 666.

261201153636 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 181680537600 + 79520616036 = 426240^2 + 281994^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 261201153636.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 35915115 + ... + 35922386.

It is an arithmetic number, because the mean of its divisors is an integer number (18522102599).

Almost surely, 2^261201153636 is an apocalyptic number.

It is an amenable number.

261201153636 is an abundant number, since it is smaller than the sum of its proper divisors (405594539928).

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

261201153636 is a wasteful number, since it uses less digits than its factorization.

261201153636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71837612 (or 71837607 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

Adding to 261201153636 its reverse (636351102162), we get a palindrome (897552255798).

The spelling of 261201153636 in words is "two hundred sixty-one billion, two hundred one million, one hundred fifty-three thousand, six hundred thirty-six".