21240204229 has 2 divisors, whose sum is σ = 21240204230. Its totient is φ = 21240204228.

The previous prime is 21240204149. The next prime is 21240204257. The reversal of 21240204229 is 92240204212.

It is an a-pointer prime, because the next prime (21240204257) can be obtained adding 21240204229 to its sum of digits (28).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12735122500 + 8505081729 = 112850^2 + 92223^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240204229 - 2²³ = 21231815621 is a prime.

It is a super-2 number, since 2×21240204229² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21240204197 and 21240204206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21240204829) 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, 10620102114 + 10620102115.

It is an arithmetic number, because the mean of its divisors is an integer number (10620102115).

Almost surely, 2^21240204229 is an apocalyptic number.

It is an amenable number.

21240204229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21240204229 is an equidigital number, since it uses as much as digits as its factorization.

21240204229 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 28.

The spelling of 21240204229 in words is "twenty-one billion, two hundred forty million, two hundred four thousand, two hundred twenty-nine".