2543508721 has 4 divisors (see below), whose sum is σ = 2739163252. Its totient is φ = 2347854192.

The previous prime is 2543508679. The next prime is 2543508733. The reversal of 2543508721 is 1278053452.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 540051121 + 2003457600 = 23239^2 + 44760^2 .

It is a cyclic number.

It is not a de Polignac number, because 2543508721 - 2¹⁷ = 2543377649 is a prime.

It is a super-2 number, since 2×2543508721² = 12938873227606111682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2543508791) 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 3 ways as a sum of consecutive naturals, for example, 97827246 + ... + 97827271.

It is an arithmetic number, because the mean of its divisors is an integer number (684790813).

Almost surely, 2^2543508721 is an apocalyptic number.

It is an amenable number.

2543508721 is a deficient number, since it is larger than the sum of its proper divisors (195654531).

2543508721 is a wasteful number, since it uses less digits than its factorization.

2543508721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195654530.

The product of its (nonzero) digits is 67200, while the sum is 37.

The square root of 2543508721 is about 50433.2104966559. The cubic root of 2543508721 is about 1365.0369592877.

The spelling of 2543508721 in words is "two billion, five hundred forty-three million, five hundred eight thousand, seven hundred twenty-one".