1165396221 has 16 divisors (see below), whose sum is σ = 1883469120. Its totient is φ = 706300560.

The previous prime is 1165396187. The next prime is 1165396231. The reversal of 1165396221 is 1226935611.

1165396221 is a `hidden beast` number, since 116 + 539 + 6 + 2 + 2 + 1 = 666.

It is not a de Polignac number, because 1165396221 - 2⁷ = 1165396093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1165396231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1961650 + ... + 1962243.

It is an arithmetic number, because the mean of its divisors is an integer number (117716820).

Almost surely, 2^1165396221 is an apocalyptic number.

1165396221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1165396221 is a deficient number, since it is larger than the sum of its proper divisors (718072899).

1165396221 is a wasteful number, since it uses less digits than its factorization.

1165396221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3923913 (or 3923907 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 1165396221 is about 34137.9000672273. The cubic root of 1165396221 is about 1052.3443374072.

It can be divided in two parts, 116539 and 6221, that added together give a triangular number (122760 = T₄₉₅).

The spelling of 1165396221 in words is "one billion, one hundred sixty-five million, three hundred ninety-six thousand, two hundred twenty-one".