1165720665 has 32 divisors (see below), whose sum is σ = 1903651200. Its totient is φ = 609016320.

The previous prime is 1165720657. The next prime is 1165720667. The reversal of 1165720665 is 5660275611.

It is not a de Polignac number, because 1165720665 - 2³ = 1165720657 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1165720667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 141510 + ... + 149520.

It is an arithmetic number, because the mean of its divisors is an integer number (59489100).

Almost surely, 2^1165720665 is an apocalyptic number.

1165720665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1165720665 is a deficient number, since it is larger than the sum of its proper divisors (737930535).

1165720665 is a wasteful number, since it uses less digits than its factorization.

1165720665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8217.

The product of its (nonzero) digits is 75600, while the sum is 39.

The square root of 1165720665 is about 34142.6516984255. The cubic root of 1165720665 is about 1052.4419852060.

The spelling of 1165720665 in words is "one billion, one hundred sixty-five million, seven hundred twenty thousand, six hundred sixty-five".