261394560 has 256 divisors, whose sum is σ = 1058515200. Its totient is φ = 59719680.

The previous prime is 261394547. The next prime is 261394561. The reversal of 261394560 is 65493162.

It is a happy number.

261394560 is a `hidden beast` number, since 2 + 6 + 1 + 3 + 94 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261394561) 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, 119880 + ... + 122040.

It is an arithmetic number, because the mean of its divisors is an integer number (4134825).

Almost surely, 2^261394560 is an apocalyptic number.

261394560 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 261394560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (529257600).

261394560 is an abundant number, since it is smaller than the sum of its proper divisors (797120640).

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

261394560 is a wasteful number, since it uses less digits than its factorization.

261394560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2196 (or 2178 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 261394560 is about 16167.7011352882. The cubic root of 261394560 is about 639.3895220341.

The spelling of 261394560 in words is "two hundred sixty-one million, three hundred ninety-four thousand, five hundred sixty".