21545113241 has 2 divisors, whose sum is σ = 21545113242. Its totient is φ = 21545113240.

The previous prime is 21545113199. The next prime is 21545113277. The reversal of 21545113241 is 14231154512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19988021641 + 1557091600 = 141379^2 + 39460^2 .

It is a cyclic number.

It is not a de Polignac number, because 21545113241 - 2¹⁰ = 21545112217 is a prime.

It is not a weakly prime, because it can be changed into another prime (21545113741) 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, 10772556620 + 10772556621.

It is an arithmetic number, because the mean of its divisors is an integer number (10772556621).

Almost surely, 2^21545113241 is an apocalyptic number.

It is an amenable number.

21545113241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21545113241 is an equidigital number, since it uses as much as digits as its factorization.

21545113241 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4800, while the sum is 29.

Adding to 21545113241 its reverse (14231154512), we get a palindrome (35776267753).

The spelling of 21545113241 in words is "twenty-one billion, five hundred forty-five million, one hundred thirteen thousand, two hundred forty-one".