3561643620 has 144 divisors (see below), whose sum is σ = 11021669568. Its totient is φ = 930758400.

The previous prime is 3561643583. The next prime is 3561643649. The reversal of 3561643620 is 263461653.

3561643620 is a `hidden beast` number, since 3 + 5 + 6 + 1 + 643 + 6 + 2 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2736970 + ... + 2738270.

It is an arithmetic number, because the mean of its divisors is an integer number (76539372).

Almost surely, 2^3561643620 is an apocalyptic number.

3561643620 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 3561643620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5510834784).

3561643620 is an abundant number, since it is smaller than the sum of its proper divisors (7460025948).

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

3561643620 is a wasteful number, since it uses less digits than its factorization.

3561643620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1610 (or 1605 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The square root of 3561643620 is about 59679.5075381827. The cubic root of 3561643620 is about 1527.1562967635.

The spelling of 3561643620 in words is "three billion, five hundred sixty-one million, six hundred forty-three thousand, six hundred twenty".