21060539 has 2 divisors, whose sum is σ = 21060540. Its totient is φ = 21060538.

The previous prime is 21060509. The next prime is 21060541. The reversal of 21060539 is 93506012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21060539 is a prime.

Together with 21060541, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_1333583 and since 21060539 and 1333583 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (21060509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10530269 + 10530270.

It is an arithmetic number, because the mean of its divisors is an integer number (10530270).

Almost surely, 2^21060539 is an apocalyptic number.

21060539 is a deficient number, since it is larger than the sum of its proper divisors (1).

21060539 is an equidigital number, since it uses as much as digits as its factorization.

21060539 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 21060539 is about 4589.1762877449. The cubic root of 21060539 is about 276.1572783829.

The spelling of 21060539 in words is "twenty-one million, sixty thousand, five hundred thirty-nine".