2165326821 has 24 divisors (see below), whose sum is σ = 3633112704. Its totient is φ = 1217043360.

The previous prime is 2165326799. The next prime is 2165326841. The reversal of 2165326821 is 1286235612.

It is not a de Polignac number, because 2165326821 - 2¹⁰ = 2165325797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2165326841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 277881 + ... + 285566.

It is an arithmetic number, because the mean of its divisors is an integer number (151379696).

Almost surely, 2^2165326821 is an apocalyptic number.

2165326821 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2165326821 is a deficient number, since it is larger than the sum of its proper divisors (1467785883).

2165326821 is a wasteful number, since it uses less digits than its factorization.

2165326821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 563521 (or 563518 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 2165326821 is about 46533.0723357055. The cubic root of 2165326821 is about 1293.7225609527.

The spelling of 2165326821 in words is "two billion, one hundred sixty-five million, three hundred twenty-six thousand, eight hundred twenty-one".