261129960 has 256 divisors, whose sum is σ = 1071705600. Its totient is φ = 55074816.

The previous prime is 261129941. The next prime is 261129983. The reversal of 261129960 is 69921162.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 96952 + ... + 99608.

It is an arithmetic number, because the mean of its divisors is an integer number (4186350).

Almost surely, 2^261129960 is an apocalyptic number.

261129960 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 261129960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (535852800).

261129960 is an abundant number, since it is smaller than the sum of its proper divisors (810575640).

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

261129960 is a wasteful number, since it uses less digits than its factorization.

261129960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2697 (or 2687 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 261129960 is about 16159.5160818633. The cubic root of 261129960 is about 639.1737057787.

The spelling of 261129960 in words is "two hundred sixty-one million, one hundred twenty-nine thousand, nine hundred sixty".