261355771400000 has 168 divisors, whose sum is σ = 648283634926200. Its totient is φ = 104535809280000.

The previous prime is 261355771399993. The next prime is 261355771400023. The reversal of 261355771400000 is 4177553162.

261355771400000 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 12 ways, for example, as 169727533314304 + 91628238085696 = 13027952^2 + 9572264^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4418570426 + ... + 4418629574.

It is an arithmetic number, because the mean of its divisors is an integer number (3858831160275).

Almost surely, 2^{261355771400000} is an apocalyptic number.

261355771400000 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 261355771400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (324141817463100).

261355771400000 is an abundant number, since it is smaller than the sum of its proper divisors (386927863526200).

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

261355771400000 is an frugal number, since it uses more digits than its factorization.

261355771400000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81279 (or 81249 counting only the distinct ones).

The product of its (nonzero) digits is 176400, while the sum is 41.

The spelling of 261355771400000 in words is "two hundred sixty-one trillion, three hundred fifty-five billion, seven hundred seventy-one million, four hundred thousand".