8243255021 has 4 divisors (see below), whose sum is σ = 8244146844. Its totient is φ = 8242363200.

The previous prime is 8243255011. The next prime is 8243255023. The reversal of 8243255021 is 1205523428.

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 1848054121 + 6395200900 = 42989^2 + 79970^2 .

It is a cyclic number.

It is not a de Polignac number, because 8243255021 - 2¹⁴ = 8243238637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8243255023) 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, 431900 + ... + 450581.

It is an arithmetic number, because the mean of its divisors is an integer number (2061036711).

Almost surely, 2^8243255021 is an apocalyptic number.

It is an amenable number.

8243255021 is a deficient number, since it is larger than the sum of its proper divisors (891823).

8243255021 is an equidigital number, since it uses as much as digits as its factorization.

8243255021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891822.

The product of its (nonzero) digits is 19200, while the sum is 32.

The square root of 8243255021 is about 90792.3731433428. The cubic root of 8243255021 is about 2020.0691919083.

Adding to 8243255021 its reverse (1205523428), we get a palindrome (9448778449).

The spelling of 8243255021 in words is "eight billion, two hundred forty-three million, two hundred fifty-five thousand, twenty-one".