243121001531 has 2 divisors, whose sum is σ = 243121001532. Its totient is φ = 243121001530.

The previous prime is 243121001491. The next prime is 243121001537. The reversal of 243121001531 is 135100121342.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243121001531 is a prime.

It is a super-2 number, since 2×243121001531² (a number of 24 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 243121001497 and 243121001506.

It is not a weakly prime, because it can be changed into another prime (243121001537) 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 as a sum of consecutive naturals, namely, 121560500765 + 121560500766.

It is an arithmetic number, because the mean of its divisors is an integer number (121560500766).

Almost surely, 2^243121001531 is an apocalyptic number.

243121001531 is a deficient number, since it is larger than the sum of its proper divisors (1).

243121001531 is an equidigital number, since it uses as much as digits as its factorization.

243121001531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 243121001531 its reverse (135100121342), we get a palindrome (378221122873).

The spelling of 243121001531 in words is "two hundred forty-three billion, one hundred twenty-one million, one thousand, five hundred thirty-one".