243997469521 has 9 divisors (see below), whose sum is σ = 264217231281. Its totient is φ = 225222505872.

The previous prime is 243997469519. The next prime is 243997469531. The reversal of 243997469521 is 125964799342.

The square root of 243997469521 is 493961.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 9586563921 + 234410905600 = 97911^2 + 484160^2 .

It is not a de Polignac number, because 243997469521 - 2¹ = 243997469519 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 243997469521.

It is not an unprimeable number, because it can be changed into a prime (243997469531) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6402495 + ... + 6440491.

Almost surely, 2^243997469521 is an apocalyptic number.

243997469521 is the 493961-st square number.

243997469521 is the 246981-st centered octagonal number.

It is an amenable number.

243997469521 is a deficient number, since it is larger than the sum of its proper divisors (20219761760).

243997469521 is an frugal number, since it uses more digits than its factorization.

243997469521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76020 (or 38010 counting only the distinct ones).

The product of its digits is 29393280, while the sum is 61.

The spelling of 243997469521 in words is "two hundred forty-three billion, nine hundred ninety-seven million, four hundred sixty-nine thousand, five hundred twenty-one".