261885879612 has 288 divisors, whose sum is σ = 818930112000. Its totient is φ = 70337030400.

The previous prime is 261885879587. The next prime is 261885879637. The reversal of 261885879612 is 216978588162.

261885879612 is a `hidden beast` number, since 2 + 6 + 1 + 8 + 8 + 5 + 8 + 7 + 9 + 612 = 666.

It is an interprime number because it is at equal distance from previous prime (261885879587) and next prime (261885879637).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a self number, because there is not a number n which added to its sum of digits gives 261885879612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 30729912 + ... + 30738432.

Almost surely, 2^261885879612 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261885879612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (409465056000).

261885879612 is an abundant number, since it is smaller than the sum of its proper divisors (557044232388).

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

261885879612 is a wasteful number, since it uses less digits than its factorization.

261885879612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8702 (or 8683 counting only the distinct ones).

The product of its digits is 23224320, while the sum is 63.

The spelling of 261885879612 in words is "two hundred sixty-one billion, eight hundred eighty-five million, eight hundred seventy-nine thousand, six hundred twelve".