261439291008 has 1536 divisors, whose sum is σ = 1023948656640. Its totient is φ = 64640581632.

The previous prime is 261439290997. The next prime is 261439291021. The reversal of 261439291008 is 800192934162.

261439291008 is a `hidden beast` number, since 2 + 614 + 3 + 9 + 29 + 1 + 0 + 0 + 8 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3149870935 + ... + 3149871017.

It is an arithmetic number, because the mean of its divisors is an integer number (666633240).

Almost surely, 2^261439291008 is an apocalyptic number.

261439291008 is a gapful number since it is divisible by the number (28) 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 261439291008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (511974328320).

261439291008 is an abundant number, since it is smaller than the sum of its proper divisors (762509365632).

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

261439291008 is a wasteful number, since it uses less digits than its factorization.

261439291008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196 (or 172 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The spelling of 261439291008 in words is "two hundred sixty-one billion, four hundred thirty-nine million, two hundred ninety-one thousand, eight".