261310406500 has 192 divisors, whose sum is σ = 671262568704. Its totient is φ = 87609600000.

The previous prime is 261310406479. The next prime is 261310406521. The reversal of 261310406500 is 5604013162.

261310406500 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261310406479) and next prime (261310406521).

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, 83724940 + ... + 83728060.

It is an arithmetic number, because the mean of its divisors is an integer number (3496159212).

Almost surely, 2^261310406500 is an apocalyptic number.

261310406500 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 261310406500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335631284352).

261310406500 is an abundant number, since it is smaller than the sum of its proper divisors (409952162204).

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

261310406500 is a wasteful number, since it uses less digits than its factorization.

261310406500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4335 (or 4323 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

Adding to 261310406500 its reverse (5604013162), we get a palindrome (266914419662).

The spelling of 261310406500 in words is "two hundred sixty-one billion, three hundred ten million, four hundred six thousand, five hundred".