3561561720 has 96 divisors (see below), whose sum is σ = 11635902720. Its totient is φ = 944759040.

The previous prime is 3561561701. The next prime is 3561561721. The reversal of 3561561720 is 271651653.

3561561720 is a `hidden beast` number, since 3 + 5 + 6 + 15 + 617 + 20 = 666.

It is a super-3 number, since 3×3561561720³ (a number of 30 digits) contains 333 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3561561721) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42862 + ... + 94658.

It is an arithmetic number, because the mean of its divisors is an integer number (121207320).

Almost surely, 2^3561561720 is an apocalyptic number.

3561561720 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 3561561720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5817951360).

3561561720 is an abundant number, since it is smaller than the sum of its proper divisors (8074341000).

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

3561561720 is a wasteful number, since it uses less digits than its factorization.

3561561720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52005 (or 51998 counting only the distinct ones).

The product of its (nonzero) digits is 37800, while the sum is 36.

The square root of 3561561720 is about 59678.8213690586. The cubic root of 3561561720 is about 1527.1445910201.

The spelling of 3561561720 in words is "three billion, five hundred sixty-one million, five hundred sixty-one thousand, seven hundred twenty".