21030242531 has 2 divisors, whose sum is σ = 21030242532. Its totient is φ = 21030242530.

The previous prime is 21030242477. The next prime is 21030242599. The reversal of 21030242531 is 13524203012.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21030242531 is a prime.

It is a super-2 number, since 2×21030242531² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21030242497 and 21030242506.

It is not a weakly prime, because it can be changed into another prime (21030242231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515121265 + 10515121266.

It is an arithmetic number, because the mean of its divisors is an integer number (10515121266).

Almost surely, 2^21030242531 is an apocalyptic number.

21030242531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030242531 is an equidigital number, since it uses as much as digits as its factorization.

21030242531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 23.

Adding to 21030242531 its reverse (13524203012), we get a palindrome (34554445543).

The spelling of 21030242531 in words is "twenty-one billion, thirty million, two hundred forty-two thousand, five hundred thirty-one".