261986647860 has 960 divisors, whose sum is σ = 1067854233600. Its totient is φ = 52364454912.

The previous prime is 261986647829. The next prime is 261986647873. The reversal of 261986647860 is 68746689162.

261986647860 is a `hidden beast` number, since 2 + 619 + 8 + 6 + 6 + 4 + 7 + 8 + 6 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 143710909 + ... + 143712731.

It is an arithmetic number, because the mean of its divisors is an integer number (1112348160).

Almost surely, 2^261986647860 is an apocalyptic number.

261986647860 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 261986647860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (533927116800).

261986647860 is an abundant number, since it is smaller than the sum of its proper divisors (805867585740).

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

261986647860 is a wasteful number, since it uses less digits than its factorization.

261986647860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1922 (or 1911 counting only the distinct ones).

The product of its (nonzero) digits is 41803776, while the sum is 63.

The spelling of 261986647860 in words is "two hundred sixty-one billion, nine hundred eighty-six million, six hundred forty-seven thousand, eight hundred sixty".