2163826721 has 12 divisors (see below), whose sum is σ = 2519410032. Its totient is φ = 1853009928.

The previous prime is 2163826703. The next prime is 2163826739. The reversal of 2163826721 is 1276283612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (2163826703) and next prime (2163826739).

It is a de Polignac number, because none of the positive numbers 2^k-2163826721 is a prime.

It is a super-3 number, since 3×2163826721³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2163826421) 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 11 ways as a sum of consecutive naturals, for example, 35366 + ... + 74688.

It is an arithmetic number, because the mean of its divisors is an integer number (209950836).

Almost surely, 2^2163826721 is an apocalyptic number.

It is an amenable number.

2163826721 is a deficient number, since it is larger than the sum of its proper divisors (355583311).

2163826721 is a wasteful number, since it uses less digits than its factorization.

2163826721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40460 (or 40453 counting only the distinct ones).

The product of its digits is 48384, while the sum is 38.

The square root of 2163826721 is about 46516.9508996452. The cubic root of 2163826721 is about 1293.4237359238.

The spelling of 2163826721 in words is "two billion, one hundred sixty-three million, eight hundred twenty-six thousand, seven hundred twenty-one".