4243254065521 has 4 divisors (see below), whose sum is σ = 4243258209652. Its totient is φ = 4243249921392.

The previous prime is 4243254065447. The next prime is 4243254065537. The reversal of 4243254065521 is 1255604523424.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 3816302903296 + 426951162225 = 1953536^2 + 653415^2 .

It is a cyclic number.

It is not a de Polignac number, because 4243254065521 - 2¹⁵ = 4243254032753 is a prime.

It is a super-2 number, since 2×4243254065521² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4243254066521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 699955 + ... + 2996071.

It is an arithmetic number, because the mean of its divisors is an integer number (1060814552413).

Almost surely, 2^{4243254065521} is an apocalyptic number.

It is an amenable number.

4243254065521 is a deficient number, since it is larger than the sum of its proper divisors (4144131).

4243254065521 is a wasteful number, since it uses less digits than its factorization.

4243254065521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4144130.

The product of its (nonzero) digits is 1152000, while the sum is 43.

Adding to 4243254065521 its reverse (1255604523424), we get a palindrome (5498858588945).

The spelling of 4243254065521 in words is "four trillion, two hundred forty-three billion, two hundred fifty-four million, sixty-five thousand, five hundred twenty-one".