2121724081 has 8 divisors (see below), whose sum is σ = 2134572264. Its totient is φ = 2108897280.

The previous prime is 2121724057. The next prime is 2121724109. The reversal of 2121724081 is 1804271212.

It can be written as a sum of positive squares in 4 ways, for example, as 1018886400 + 1102837681 = 31920^2 + 33209^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2121724081 is a prime.

It is a super-2 number, since 2×2121724081² = 9003426151790589122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121724001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 222471 + ... + 231811.

It is an arithmetic number, because the mean of its divisors is an integer number (266821533).

Almost surely, 2^2121724081 is an apocalyptic number.

It is an amenable number.

2121724081 is a deficient number, since it is larger than the sum of its proper divisors (12848183).

2121724081 is a wasteful number, since it uses less digits than its factorization.

2121724081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10691.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 2121724081 is about 46062.1762512368. The cubic root of 2121724081 is about 1284.9798037674.

Adding to 2121724081 its reverse (1804271212), we get a palindrome (3925995293).

The spelling of 2121724081 in words is "two billion, one hundred twenty-one million, seven hundred twenty-four thousand, eighty-one".