61665606565 has 24 divisors (see below), whose sum is σ = 76526387064. Its totient is φ = 47701411200.

The previous prime is 61665606533. The next prime is 61665606571. The reversal of 61665606565 is 56560656616.

It can be written as a sum of positive squares in 4 ways, for example, as 130850721 + 61534755844 = 11439^2 + 248062^2 .

It is not a de Polignac number, because 61665606565 - 2⁵ = 61665606533 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 6631059 + ... + 6640351.

It is an arithmetic number, because the mean of its divisors is an integer number (3188599461).

Almost surely, 2^61665606565 is an apocalyptic number.

It is an amenable number.

61665606565 is a deficient number, since it is larger than the sum of its proper divisors (14860780499).

61665606565 is a wasteful number, since it uses less digits than its factorization.

61665606565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10741 (or 10710 counting only the distinct ones).

The product of its (nonzero) digits is 5832000, while the sum is 52.

The spelling of 61665606565 in words is "sixty-one billion, six hundred sixty-five million, six hundred six thousand, five hundred sixty-five".