21021871229 has 2 divisors, whose sum is σ = 21021871230. Its totient is φ = 21021871228.

The previous prime is 21021871193. The next prime is 21021871303. The reversal of 21021871229 is 92217812012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15527652100 + 5494219129 = 124610^2 + 74123^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021871229 - 2⁸ = 21021870973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021811229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510935614 + 10510935615.

It is an arithmetic number, because the mean of its divisors is an integer number (10510935615).

Almost surely, 2^21021871229 is an apocalyptic number.

It is an amenable number.

21021871229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021871229 is an equidigital number, since it uses as much as digits as its factorization.

21021871229 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 35.

The spelling of 21021871229 in words is "twenty-one billion, twenty-one million, eight hundred seventy-one thousand, two hundred twenty-nine".