20509118 has 16 divisors (see below), whose sum is σ = 35489664. Its totient is φ = 8706840.

The previous prime is 20509117. The next prime is 20509127. The reversal of 20509118 is 81190502.

It is a happy number.

It is a super-2 number, since 2×20509118² = 841247842275848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20509117) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5348 + ... + 8343.

It is an arithmetic number, because the mean of its divisors is an integer number (2218104).

Almost surely, 2^20509118 is an apocalyptic number.

20509118 is a deficient number, since it is larger than the sum of its proper divisors (14980546).

20509118 is a wasteful number, since it uses less digits than its factorization.

20509118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13807.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 20509118 is about 4528.6993717844. The cubic root of 20509118 is about 273.7257543354.

The spelling of 20509118 in words is "twenty million, five hundred nine thousand, one hundred eighteen".