21100529 has 2 divisors, whose sum is σ = 21100530. Its totient is φ = 21100528.

The previous prime is 21100517. The next prime is 21100531. The reversal of 21100529 is 92500112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19562929 + 1537600 = 4423^2 + 1240^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100529 - 2²⁰ = 20051953 is a prime.

It is a Sophie Germain prime.

Together with 21100531, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21100529.

It is not a weakly prime, because it can be changed into another prime (21100559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550264 + 10550265.

It is an arithmetic number, because the mean of its divisors is an integer number (10550265).

Almost surely, 2^21100529 is an apocalyptic number.

It is an amenable number.

21100529 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100529 is an equidigital number, since it uses as much as digits as its factorization.

21100529 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 20.

The square root of 21100529 is about 4593.5312124770. The cubic root of 21100529 is about 276.3319581013.

The spelling of 21100529 in words is "twenty-one million, one hundred thousand, five hundred twenty-nine".