261605376 has 240 divisors, whose sum is σ = 832431600. Its totient is φ = 81616896.

The previous prime is 261605359. The next prime is 261605387. The reversal of 261605376 is 673506162.

261605376 is a `hidden beast` number, since 2 + 61 + 60 + 537 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 261605376.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3151831 + ... + 3151913.

It is an arithmetic number, because the mean of its divisors is an integer number (3468465).

Almost surely, 2^261605376 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 261605376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (416215800).

261605376 is an abundant number, since it is smaller than the sum of its proper divisors (570826224).

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

261605376 is an equidigital number, since it uses as much as digits as its factorization.

261605376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 107 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 36.

The square root of 261605376 is about 16174.2194865780. The cubic root of 261605376 is about 639.5613661108.

The spelling of 261605376 in words is "two hundred sixty-one million, six hundred five thousand, three hundred seventy-six".