261266194944 has 480 divisors, whose sum is σ = 817049067120. Its totient is φ = 80188932096.

The previous prime is 261266194913. The next prime is 261266194967. The reversal of 261266194944 is 449491662162.

261266194944 is a `hidden beast` number, since 2 + 6 + 12 + 6 + 619 + 4 + 9 + 4 + 4 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 247717234944 + 13548960000 = 497712^2 + 116400^2 .

It is a super-2 number, since 2×261266194944² (a number of 24 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 262051854 + ... + 262052850.

Almost surely, 2^261266194944 is an apocalyptic number.

261266194944 is a gapful number since it is divisible by the number (24) 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 261266194944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (408524533560).

261266194944 is an abundant number, since it is smaller than the sum of its proper divisors (555782872176).

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

261266194944 is a wasteful number, since it uses less digits than its factorization.

261266194944 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1140 (or 1121 counting only the distinct ones).

The product of its digits is 4478976, while the sum is 54.

The spelling of 261266194944 in words is "two hundred sixty-one billion, two hundred sixty-six million, one hundred ninety-four thousand, nine hundred forty-four".