261111340800 has 540 divisors, whose sum is σ = 975201994536. Its totient is φ = 68926464000.

The previous prime is 261111340771. The next prime is 261111340811. The reversal of 261111340800 is 8043111162.

It is a happy number.

261111340800 is a `hidden beast` number, since 2 + 611 + 1 + 1 + 3 + 40 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (540).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 52355907 + ... + 52360893.

Almost surely, 2^261111340800 is an apocalyptic number.

261111340800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261111340800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (487600997268).

261111340800 is an abundant number, since it is smaller than the sum of its proper divisors (714090653736).

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

261111340800 is a wasteful number, since it uses less digits than its factorization.

261111340800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5126 (or 5098 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

Adding to 261111340800 its reverse (8043111162), we get a palindrome (269154451962).

The spelling of 261111340800 in words is "two hundred sixty-one billion, one hundred eleven million, three hundred forty thousand, eight hundred".