1165388821 has 8 divisors (see below), whose sum is σ = 1183695584. Its totient is φ = 1147109040.

The previous prime is 1165388789. The next prime is 1165388837. The reversal of 1165388821 is 1288835611.

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 1165388821 - 2⁵ = 1165388789 is a prime.

It is a super-2 number, since 2×1165388821² = 2716262208223540082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1165388321) 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, 91366 + ... + 103336.

It is an arithmetic number, because the mean of its divisors is an integer number (147961948).

Almost surely, 2^1165388821 is an apocalyptic number.

It is an amenable number.

1165388821 is a deficient number, since it is larger than the sum of its proper divisors (18306763).

1165388821 is a wasteful number, since it uses less digits than its factorization.

1165388821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13491.

The product of its digits is 92160, while the sum is 43.

The square root of 1165388821 is about 34137.7916831186. The cubic root of 1165388821 is about 1052.3421100204.

The spelling of 1165388821 in words is "one billion, one hundred sixty-five million, three hundred eighty-eight thousand, eight hundred twenty-one".