4561561665 has 24 divisors (see below), whose sum is σ = 7908294888. Its totient is φ = 2432344320.

The previous prime is 4561561651. The next prime is 4561561679. The reversal of 4561561665 is 5661651654.

It is an interprime number because it is at equal distance from previous prime (4561561651) and next prime (4561561679).

It can be written as a sum of positive squares in 4 ways, for example, as 1871687169 + 2689874496 = 43263^2 + 51864^2 .

It is not a de Polignac number, because 4561561665 - 2⁹ = 4561561153 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 4561561665.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 384807 + ... + 396483.

It is an arithmetic number, because the mean of its divisors is an integer number (329512287).

Almost surely, 2^4561561665 is an apocalyptic number.

4561561665 is a gapful number since it is divisible by the number (45) formed by its first and last digit.

It is an amenable number.

4561561665 is a deficient number, since it is larger than the sum of its proper divisors (3346733223).

4561561665 is a wasteful number, since it uses less digits than its factorization.

4561561665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20369 (or 20366 counting only the distinct ones).

The product of its digits is 648000, while the sum is 45.

The square root of 4561561665 is about 67539.3342060758. The cubic root of 4561561665 is about 1658.4581494285.

The spelling of 4561561665 in words is "four billion, five hundred sixty-one million, five hundred sixty-one thousand, six hundred sixty-five".