261331510206 has 64 divisors (see below), whose sum is σ = 575506326528. Its totient is φ = 78608147328.

The previous prime is 261331510199. The next prime is 261331510211. The reversal of 261331510206 is 602015133162.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3174441 + ... + 3255723.

It is an arithmetic number, because the mean of its divisors is an integer number (8992286352).

Almost surely, 2^261331510206 is an apocalyptic number.

261331510206 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 261331510206, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287753163264).

261331510206 is an abundant number, since it is smaller than the sum of its proper divisors (314174816322).

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

261331510206 is a wasteful number, since it uses less digits than its factorization.

261331510206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82225.

The product of its (nonzero) digits is 6480, while the sum is 30.

Adding to 261331510206 its reverse (602015133162), we get a palindrome (863346643368).

The spelling of 261331510206 in words is "two hundred sixty-one billion, three hundred thirty-one million, five hundred ten thousand, two hundred six".