21011511229 has 2 divisors, whose sum is σ = 21011511230. Its totient is φ = 21011511228.

The previous prime is 21011511211. The next prime is 21011511239. The reversal of 21011511229 is 92211511012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18070618329 + 2940892900 = 134427^2 + 54230^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011511229 - 2³³ = 12421576637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21011511239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505755614 + 10505755615.

It is an arithmetic number, because the mean of its divisors is an integer number (10505755615).

Almost surely, 2^21011511229 is an apocalyptic number.

It is an amenable number.

21011511229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011511229 is an equidigital number, since it uses as much as digits as its factorization.

21011511229 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 25.

The spelling of 21011511229 in words is "twenty-one billion, eleven million, five hundred eleven thousand, two hundred twenty-nine".