261043500 has 192 divisors, whose sum is σ = 834986880. Its totient is φ = 63078400.

The previous prime is 261043493. The next prime is 261043511. The reversal of 261043500 is 5340162.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 739324 + ... + 739676.

It is an arithmetic number, because the mean of its divisors is an integer number (4348890).

Almost surely, 2^261043500 is an apocalyptic number.

261043500 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 261043500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (417493440).

261043500 is an abundant number, since it is smaller than the sum of its proper divisors (573943380).

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

261043500 is a wasteful number, since it uses less digits than its factorization.

261043500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421 (or 409 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 261043500 is about 16156.8406565145. The cubic root of 261043500 is about 639.1031546262.

Adding to 261043500 its reverse (5340162), we get a palindrome (266383662).

The spelling of 261043500 in words is "two hundred sixty-one million, forty-three thousand, five hundred".