3561281665 has 12 divisors (see below), whose sum is σ = 4284289404. Its totient is φ = 2841875456.

The previous prime is 3561281651. The next prime is 3561281683. The reversal of 3561281665 is 5661821653.

It can be written as a sum of positive squares in 6 ways, for example, as 159592689 + 3401688976 = 12633^2 + 58324^2 .

It is not a de Polignac number, because 3561281665 - 2¹³ = 3561273473 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1006239 + ... + 1009771.

It is an arithmetic number, because the mean of its divisors is an integer number (357024117).

Almost surely, 2^3561281665 is an apocalyptic number.

It is an amenable number.

3561281665 is a deficient number, since it is larger than the sum of its proper divisors (723007739).

3561281665 is an frugal number, since it uses more digits than its factorization.

3561281665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4436 (or 3987 counting only the distinct ones).

The product of its digits is 259200, while the sum is 43.

The square root of 3561281665 is about 59676.4749712984. The cubic root of 3561281665 is about 1527.1045621673.

The spelling of 3561281665 in words is "three billion, five hundred sixty-one million, two hundred eighty-one thousand, six hundred sixty-five".