261047178 has 64 divisors (see below), whose sum is σ = 665521920. Its totient is φ = 74298816.

The previous prime is 261047177. The next prime is 261047239. The reversal of 261047178 is 871740162.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261047177) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 109576 + ... + 111932.

It is an arithmetic number, because the mean of its divisors is an integer number (10398780).

Almost surely, 2^261047178 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261047178, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (332760960).

261047178 is an abundant number, since it is smaller than the sum of its proper divisors (404474742).

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

261047178 is a wasteful number, since it uses less digits than its factorization.

261047178 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668 (or 2662 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 261047178 is about 16156.9544778711. The cubic root of 261047178 is about 639.1061561826.

The spelling of 261047178 in words is "two hundred sixty-one million, forty-seven thousand, one hundred seventy-eight".