21036539 has 2 divisors, whose sum is σ = 21036540. Its totient is φ = 21036538.

The previous prime is 21036527. The next prime is 21036563. The reversal of 21036539 is 93563012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21036539 - 2²⁴ = 4259323 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21036139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10518269 + 10518270.

It is an arithmetic number, because the mean of its divisors is an integer number (10518270).

Almost surely, 2^21036539 is an apocalyptic number.

21036539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21036539 is an equidigital number, since it uses as much as digits as its factorization.

21036539 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4860, while the sum is 29.

The square root of 21036539 is about 4586.5606940277. The cubic root of 21036539 is about 276.0523381456.

The spelling of 21036539 in words is "twenty-one million, thirty-six thousand, five hundred thirty-nine".