20509011 has 32 divisors (see below), whose sum is σ = 31795200. Its totient is φ = 13050720.

The previous prime is 20508997. The next prime is 20509057. The reversal of 20509011 is 11090502.

It is not a de Polignac number, because 20509011 - 2⁷ = 20508883 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20509081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 89445 + ... + 89673.

It is an arithmetic number, because the mean of its divisors is an integer number (993600).

Almost surely, 2^20509011 is an apocalyptic number.

20509011 is a deficient number, since it is larger than the sum of its proper divisors (11286189).

20509011 is a wasteful number, since it uses less digits than its factorization.

20509011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376 (or 370 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 18.

The square root of 20509011 is about 4528.6875582226. The cubic root of 20509011 is about 273.7252783080.

Adding to 20509011 its reverse (11090502), we get a palindrome (31599513).

The spelling of 20509011 in words is "twenty million, five hundred nine thousand, eleven".