20538636 has 12 divisors (see below), whose sum is σ = 47923512. Its totient is φ = 6846208.

The previous prime is 20538631. The next prime is 20538643. The reversal of 20538636 is 63683502.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 20538597 and 20538606.

It is not an unprimeable number, because it can be changed into a prime (20538631) 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, 855765 + ... + 855788.

It is an arithmetic number, because the mean of its divisors is an integer number (3993626).

Almost surely, 2^20538636 is an apocalyptic number.

It is an amenable number.

20538636 is an abundant number, since it is smaller than the sum of its proper divisors (27384876).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20538636 is a wasteful number, since it uses less digits than its factorization.

20538636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1711560 (or 1711558 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 33.

The square root of 20538636 is about 4531.9571930900. The cubic root of 20538636 is about 273.8570124353.

The spelling of 20538636 in words is "twenty million, five hundred thirty-eight thousand, six hundred thirty-six".