261192521616 has 160 divisors (see below), whose sum is σ = 758831431680. Its totient is φ = 76813220352.

The previous prime is 261192521591. The next prime is 261192521701. The reversal of 261192521616 is 616125291162.

It is a happy 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 31 ways as a sum of consecutive naturals, for example, 20646205 + ... + 20658851.

It is an arithmetic number, because the mean of its divisors is an integer number (4742696448).

Almost surely, 2^261192521616 is an apocalyptic number.

261192521616 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 261192521616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (379415715840).

261192521616 is an abundant number, since it is smaller than the sum of its proper divisors (497638910064).

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

261192521616 is a wasteful number, since it uses less digits than its factorization.

261192521616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14133 (or 14127 counting only the distinct ones).

The product of its digits is 77760, while the sum is 42.

The spelling of 261192521616 in words is "two hundred sixty-one billion, one hundred ninety-two million, five hundred twenty-one thousand, six hundred sixteen".