20131918 has 8 divisors (see below), whose sum is σ = 30217248. Its totient is φ = 10059504.

The previous prime is 20131907. The next prime is 20131919. The reversal of 20131918 is 81913102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 20131892 and 20131901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20131919) 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, 3355 + ... + 7177.

It is an arithmetic number, because the mean of its divisors is an integer number (3777156).

Almost surely, 2^20131918 is an apocalyptic number.

20131918 is a deficient number, since it is larger than the sum of its proper divisors (10085330).

20131918 is a wasteful number, since it uses less digits than its factorization.

20131918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6458.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 20131918 is about 4486.8605951155. The cubic root of 20131918 is about 272.0372552055.

The spelling of 20131918 in words is "twenty million, one hundred thirty-one thousand, nine hundred eighteen".