261219218688 has 108 divisors (see below), whose sum is σ = 753845912820. Its totient is φ = 86993707008.

The previous prime is 261219218677. The next prime is 261219218707. The reversal of 261219218688 is 886812912162.

261219218688 is a `hidden beast` number, since 2 + 612 + 1 + 9 + 2 + 18 + 6 + 8 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 46842810624 + 214376408064 = 216432^2 + 463008^2 .

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2504020 + ... + 2606252.

Almost surely, 2^261219218688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261219218688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (376922956410).

261219218688 is an abundant number, since it is smaller than the sum of its proper divisors (492626694132).

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

261219218688 is a wasteful number, since it uses less digits than its factorization.

261219218688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103364 (or 103347 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 54.

The spelling of 261219218688 in words is "two hundred sixty-one billion, two hundred nineteen million, two hundred eighteen thousand, six hundred eighty-eight".