261669578112 has 256 divisors, whose sum is σ = 792480024000. Its totient is φ = 84950138880.

The previous prime is 261669578111. The next prime is 261669578119. The reversal of 261669578112 is 211875966162.

It is a happy number.

261669578112 is a `hidden beast` number, since 2 + 6 + 1 + 6 + 69 + 578 + 1 + 1 + 2 = 666.

261669578112 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261669578111) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 109529814 + ... + 109532202.

Almost surely, 2^261669578112 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 261669578112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (396240012000).

261669578112 is an abundant number, since it is smaller than the sum of its proper divisors (530810445888).

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

261669578112 is a wasteful number, since it uses less digits than its factorization.

261669578112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3226 (or 3208 counting only the distinct ones).

The product of its digits is 2177280, while the sum is 54.

The spelling of 261669578112 in words is "two hundred sixty-one billion, six hundred sixty-nine million, five hundred seventy-eight thousand, one hundred twelve".