243513021 has 16 divisors (see below), whose sum is σ = 334065600. Its totient is φ = 157667328.

The previous prime is 243513007. The next prime is 243513043. The reversal of 243513021 is 120315342.

It is not a de Polignac number, because 243513021 - 2⁶ = 243512957 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (243513071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71485 + ... + 74813.

It is an arithmetic number, because the mean of its divisors is an integer number (20879100).

Almost surely, 2^243513021 is an apocalyptic number.

It is an amenable number.

243513021 is a deficient number, since it is larger than the sum of its proper divisors (90552579).

243513021 is a wasteful number, since it uses less digits than its factorization.

243513021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4028.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 243513021 is about 15604.9037485016. The cubic root of 243513021 is about 624.4639850188.

Adding to 243513021 its reverse (120315342), we get a palindrome (363828363).

It can be divided in two parts, 24351 and 3021, that added together give a palindrome (27372).

The spelling of 243513021 in words is "two hundred forty-three million, five hundred thirteen thousand, twenty-one".