261685600 has 144 divisors (see below), whose sum is σ = 705329856. Its totient is φ = 94016000.

The previous prime is 261685577. The next prime is 261685603. The reversal of 261685600 is 6586162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261685603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1152687 + ... + 1152913.

It is an arithmetic number, because the mean of its divisors is an integer number (4898124).

Almost surely, 2^261685600 is an apocalyptic number.

261685600 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 261685600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (352664928).

261685600 is an abundant number, since it is smaller than the sum of its proper divisors (443644256).

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

261685600 is a wasteful number, since it uses less digits than its factorization.

261685600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 376 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 261685600 is about 16176.6992925009. The cubic root of 261685600 is about 639.6267354698.

The spelling of 261685600 in words is "two hundred sixty-one million, six hundred eighty-five thousand, six hundred".