1165541621 has 8 divisors (see below), whose sum is σ = 1178315544. Its totient is φ = 1152783360.

The previous prime is 1165541593. The next prime is 1165541633. The reversal of 1165541621 is 1261455611.

It can be written as a sum of positive squares in 4 ways, for example, as 343396 + 1165198225 = 586^2 + 34135^2 .

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 1165541621 - 2⁶ = 1165541557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1165541651) 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, 206051 + ... + 211631.

It is an arithmetic number, because the mean of its divisors is an integer number (147289443).

Almost surely, 2^1165541621 is an apocalyptic number.

It is an amenable number.

1165541621 is a deficient number, since it is larger than the sum of its proper divisors (12773923).

1165541621 is an equidigital number, since it uses as much as digits as its factorization.

1165541621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7831.

The product of its digits is 7200, while the sum is 32.

The square root of 1165541621 is about 34140.0295986984. The cubic root of 1165541621 is about 1052.3881006358.

The spelling of 1165541621 in words is "one billion, one hundred sixty-five million, five hundred forty-one thousand, six hundred twenty-one".