261005064216 has 144 divisors (see below), whose sum is σ = 724239548280. Its totient is φ = 78348441600.

The previous prime is 261005064197. The next prime is 261005064223. The reversal of 261005064216 is 612460500162.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 6798996 + ... + 6837276.

Almost surely, 2^261005064216 is an apocalyptic number.

261005064216 is a gapful number since it is divisible by the number (26) 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 261005064216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362119774140).

261005064216 is an abundant number, since it is smaller than the sum of its proper divisors (463234484064).

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

261005064216 is a wasteful number, since it uses less digits than its factorization.

261005064216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38398 (or 38340 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

Adding to 261005064216 its reverse (612460500162), we get a palindrome (873465564378).

The spelling of 261005064216 in words is "two hundred sixty-one billion, five million, sixty-four thousand, two hundred sixteen".