21062539 has 4 divisors (see below), whose sum is σ = 21111840. Its totient is φ = 21013240.

The previous prime is 21062527. The next prime is 21062543. The reversal of 21062539 is 93526012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21062539 - 2¹¹ = 21060491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21062519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24004 + ... + 24865.

It is an arithmetic number, because the mean of its divisors is an integer number (5277960).

Almost surely, 2^21062539 is an apocalyptic number.

21062539 is a deficient number, since it is larger than the sum of its proper divisors (49301).

21062539 is an equidigital number, since it uses as much as digits as its factorization.

21062539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49300.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 21062539 is about 4589.3941866002. The cubic root of 21062539 is about 276.1660198033.

The spelling of 21062539 in words is "twenty-one million, sixty-two thousand, five hundred thirty-nine".