3261565440 has 720 divisors, whose sum is σ = 13753932192. Its totient is φ = 738533376.

The previous prime is 3261565399. The next prime is 3261565453. The reversal of 3261565440 is 445651623.

3261565440 is a `hidden beast` number, since 3 + 2 + 61 + 56 + 544 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

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

It is a junction number, because it is equal to n+sod(n) for n = 3261565395 and 3261565404.

It is an unprimeable number.

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 71 ways as a sum of consecutive naturals, for example, 30481867 + ... + 30481973.

Almost surely, 2^3261565440 is an apocalyptic number.

3261565440 is a gapful number since it is divisible by the number (30) 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 3261565440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6876966096).

3261565440 is an abundant number, since it is smaller than the sum of its proper divisors (10492366752).

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

3261565440 is an equidigital number, since it uses as much as digits as its factorization.

3261565440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 3261565440 is about 57110.1167920361. The cubic root of 3261565440 is about 1483.0030089967.

The spelling of 3261565440 in words is "three billion, two hundred sixty-one million, five hundred sixty-five thousand, four hundred forty".