243128729 has 12 divisors (see below), whose sum is σ = 253022868. Its totient is φ = 233481600.

The previous prime is 243128623. The next prime is 243128749. The reversal of 243128729 is 927821342.

It can be written as a sum of positive squares in 2 ways, for example, as 114918400 + 128210329 = 10720^2 + 11323^2 .

It is not a de Polignac number, because 243128729 - 2¹⁶ = 243063193 is a prime.

It is a super-2 number, since 2×243128729² = 118223157730310882, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 243128692 and 243128701.

It is not an unprimeable number, because it can be changed into a prime (243128749) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 183389 + ... + 184709.

It is an arithmetic number, because the mean of its divisors is an integer number (21085239).

Almost surely, 2^243128729 is an apocalyptic number.

It is an amenable number.

243128729 is a deficient number, since it is larger than the sum of its proper divisors (9894139).

243128729 is an equidigital number, since it uses as much as digits as its factorization.

243128729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1496 (or 1429 counting only the distinct ones).

The product of its digits is 48384, while the sum is 38.

The square root of 243128729 is about 15592.5857060335. The cubic root of 243128729 is about 624.1353196897.

The spelling of 243128729 in words is "two hundred forty-three million, one hundred twenty-eight thousand, seven hundred twenty-nine".