21142529 has 2 divisors, whose sum is σ = 21142530. Its totient is φ = 21142528.

The previous prime is 21142493. The next prime is 21142531. The reversal of 21142529 is 92524112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20948929 + 193600 = 4577^2 + 440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21142529 - 2⁸ = 21142273 is a prime.

It is a Sophie Germain prime.

Together with 21142531, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21142498 and 21142507.

It is not a weakly prime, because it can be changed into another prime (21142729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571264 + 10571265.

It is an arithmetic number, because the mean of its divisors is an integer number (10571265).

Almost surely, 2^21142529 is an apocalyptic number.

It is an amenable number.

21142529 is a deficient number, since it is larger than the sum of its proper divisors (1).

21142529 is an equidigital number, since it uses as much as digits as its factorization.

21142529 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 26.

The square root of 21142529 is about 4598.1005861116. The cubic root of 21142529 is about 276.5151802109.

The spelling of 21142529 in words is "twenty-one million, one hundred forty-two thousand, five hundred twenty-nine".