1205561665 has 16 divisors (see below), whose sum is σ = 1803646080. Its totient is φ = 751518720.

The previous prime is 1205561659. The next prime is 1205561671. The reversal of 1205561665 is 5661655021.

It is an interprime number because it is at equal distance from previous prime (1205561659) and next prime (1205561671).

It is not a de Polignac number, because 1205561665 - 2¹¹ = 1205559617 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1565280 + ... + 1566049.

It is an arithmetic number, because the mean of its divisors is an integer number (112727880).

Almost surely, 2^1205561665 is an apocalyptic number.

It is an amenable number.

1205561665 is a deficient number, since it is larger than the sum of its proper divisors (598084415).

1205561665 is a wasteful number, since it uses less digits than its factorization.

1205561665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3131352.

The product of its (nonzero) digits is 54000, while the sum is 37.

The square root of 1205561665 is about 34721.1990720367. The cubic root of 1205561665 is about 1064.2977480091.

It can be divided in two parts, 120556 and 1665, that added together give a palindrome (122221).

The spelling of 1205561665 in words is "one billion, two hundred five million, five hundred sixty-one thousand, six hundred sixty-five".