261728935650 has 432 divisors, whose sum is σ = 890080859304. Its totient is φ = 54646824960.

The previous prime is 261728935609. The next prime is 261728935667. The reversal of 261728935650 is 56539827162.

261728935650 is a `hidden beast` number, since 2 + 6 + 1 + 7 + 289 + 356 + 5 + 0 = 666.

261728935650 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 12 ways, for example, as 40077237249 + 221651698401 = 200193^2 + 470799^2 .

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 27800344 + ... + 27809756.

Almost surely, 2^261728935650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261728935650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (445040429652).

261728935650 is an abundant number, since it is smaller than the sum of its proper divisors (628351923654).

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

261728935650 is a wasteful number, since it uses less digits than its factorization.

261728935650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9555 (or 9540 counting only the distinct ones).

The product of its (nonzero) digits is 5443200, while the sum is 54.

It can be divided in two parts, 261728 and 935650, that added together give a triangular number (1197378 = T₁₅₄₇).

The spelling of 261728935650 in words is "two hundred sixty-one billion, seven hundred twenty-eight million, nine hundred thirty-five thousand, six hundred fifty".