261545760 has 432 divisors, whose sum is σ = 1093030848. Its totient is φ = 57853440.

The previous prime is 261545749. The next prime is 261545783. The reversal of 261545760 is 67545162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (432).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8436945 + ... + 8436975.

It is an arithmetic number, because the mean of its divisors is an integer number (2530164).

Almost surely, 2^261545760 is an apocalyptic number.

261545760 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 261545760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (546515424).

261545760 is an abundant number, since it is smaller than the sum of its proper divisors (831485088).

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

261545760 is an equidigital number, since it uses as much as digits as its factorization.

261545760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99 (or 48 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The square root of 261545760 is about 16172.3764487474. The cubic root of 261545760 is about 639.5127802247.

The spelling of 261545760 in words is "two hundred sixty-one million, five hundred forty-five thousand, seven hundred sixty".