243121155525 has 18 divisors (see below), whose sum is σ = 435457003410. Its totient is φ = 129664616160.

The previous prime is 243121155503. The next prime is 243121155539. The reversal of 243121155525 is 525551121342.

243121155525 is a `hidden beast` number, since 2 + 4 + 3 + 12 + 115 + 5 + 525 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 14658187041 + 228462968484 = 121071^2 + 477978^2 .

It is not a de Polignac number, because 243121155525 - 2⁸ = 243121155269 is a prime.

It is a super-2 number, since 2×243121155525² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 243121155525.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 540269010 + ... + 540269459.

It is an arithmetic number, because the mean of its divisors is an integer number (24192055745).

Almost surely, 2^243121155525 is an apocalyptic number.

243121155525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

243121155525 is a deficient number, since it is larger than the sum of its proper divisors (192335847885).

243121155525 is a wasteful number, since it uses less digits than its factorization.

243121155525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1080538485 (or 1080538477 counting only the distinct ones).

The product of its digits is 60000, while the sum is 36.

Adding to 243121155525 its reverse (525551121342), we get a palindrome (768672276867).

The spelling of 243121155525 in words is "two hundred forty-three billion, one hundred twenty-one million, one hundred fifty-five thousand, five hundred twenty-five".