20912539 has 4 divisors (see below), whose sum is σ = 20923056. Its totient is φ = 20902024.

The previous prime is 20912537. The next prime is 20912561. The reversal of 20912539 is 93521902.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20912539 - 2¹ = 20912537 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20912539.

It is not an unprimeable number, because it can be changed into a prime (20912531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1264 + ... + 6589.

It is an arithmetic number, because the mean of its divisors is an integer number (5230764).

Almost surely, 2^20912539 is an apocalyptic number.

20912539 is a deficient number, since it is larger than the sum of its proper divisors (10517).

20912539 is an equidigital number, since it uses as much as digits as its factorization.

20912539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10516.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 20912539 is about 4573.0229607996. The cubic root of 20912539 is about 275.5088715560.

The spelling of 20912539 in words is "twenty million, nine hundred twelve thousand, five hundred thirty-nine".