261005500 has 48 divisors (see below), whose sum is σ = 651478464. Its totient is φ = 89486400.

The previous prime is 261005483. The next prime is 261005501. The reversal of 261005500 is 5500162.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261005501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33787 + ... + 40786.

It is an arithmetic number, because the mean of its divisors is an integer number (13572468).

Almost surely, 2^261005500 is an apocalyptic number.

261005500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261005500 is an abundant number, since it is smaller than the sum of its proper divisors (390472964).

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

261005500 is a wasteful number, since it uses less digits than its factorization.

261005500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74599 (or 74587 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 261005500 is about 16155.6646412334. The cubic root of 261005500 is about 639.0721417894.

Adding to 261005500 its reverse (5500162), we get a palindrome (266505662).

The spelling of 261005500 in words is "two hundred sixty-one million, five thousand, five hundred".