243420354521 has 4 divisors (see below), whose sum is σ = 243741914532. Its totient is φ = 243098794512.

The previous prime is 243420354493. The next prime is 243420354523. The reversal of 243420354521 is 125453024342.

It is a happy number.

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 100086180496 + 143334174025 = 316364^2 + 378595^2 .

It is a cyclic number.

It is not a de Polignac number, because 243420354521 - 2³⁴ = 226240485337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (243420354523) 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, 160778870 + ... + 160780383.

It is an arithmetic number, because the mean of its divisors is an integer number (60935478633).

Almost surely, 2^243420354521 is an apocalyptic number.

It is an amenable number.

243420354521 is a deficient number, since it is larger than the sum of its proper divisors (321560011).

243420354521 is an equidigital number, since it uses as much as digits as its factorization.

243420354521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321560010.

The product of its (nonzero) digits is 115200, while the sum is 35.

Adding to 243420354521 its reverse (125453024342), we get a palindrome (368873378863).

The spelling of 243420354521 in words is "two hundred forty-three billion, four hundred twenty million, three hundred fifty-four thousand, five hundred twenty-one".