3661561855 has 8 divisors (see below), whose sum is σ = 5021570592. Its totient is φ = 2510785248.

The previous prime is 3661561853. The next prime is 3661561901. The reversal of 3661561855 is 5581651663.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3661561855 - 2¹ = 3661561853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3661561853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52307992 + ... + 52308061.

It is an arithmetic number, because the mean of its divisors is an integer number (627696324).

Almost surely, 2^3661561855 is an apocalyptic number.

3661561855 is a gapful number since it is divisible by the number (35) formed by its first and last digit.

3661561855 is a deficient number, since it is larger than the sum of its proper divisors (1360008737).

3661561855 is a wasteful number, since it uses less digits than its factorization.

3661561855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104616065.

The product of its digits is 648000, while the sum is 46.

The square root of 3661561855 is about 60510.8408055945. The cubic root of 3661561855 is about 1541.3057255365.

It can be divided in two parts, 3661 and 561855, that added together give a triangular number (565516 = T₁₀₆₃).

The spelling of 3661561855 in words is "three billion, six hundred sixty-one million, five hundred sixty-one thousand, eight hundred fifty-five".