261445760 has 64 divisors (see below), whose sum is σ = 633052800. Its totient is φ = 103234560.

The previous prime is 261445711. The next prime is 261445763. The reversal of 261445760 is 67544162.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 261445760.

It is not an unprimeable number, because it can be changed into a prime (261445763) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47975 + ... + 53145.

It is an arithmetic number, because the mean of its divisors is an integer number (9891450).

Almost surely, 2^261445760 is an apocalyptic number.

261445760 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 261445760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (316526400).

261445760 is an abundant number, since it is smaller than the sum of its proper divisors (371607040).

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

261445760 is an equidigital number, since it uses as much as digits as its factorization.

261445760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5269 (or 5257 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 35.

The square root of 261445760 is about 16169.2844615957. The cubic root of 261445760 is about 639.4312655786.

The spelling of 261445760 in words is "two hundred sixty-one million, four hundred forty-five thousand, seven hundred sixty".