18720011 has 4 divisors (see below), whose sum is σ = 18774000. Its totient is φ = 18666024.

The previous prime is 18719983. The next prime is 18720083. The reversal of 18720011 is 11002781.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18720011 - 2¹⁴ = 18703627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18723011) 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, 26471 + ... + 27168.

It is an arithmetic number, because the mean of its divisors is an integer number (4693500).

Almost surely, 2^18720011 is an apocalyptic number.

18720011 is a deficient number, since it is larger than the sum of its proper divisors (53989).

18720011 is an equidigital number, since it uses as much as digits as its factorization.

18720011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53988.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 18720011 is about 4326.6628017446. The cubic root of 18720011 is about 265.5229308600.

Adding to 18720011 its reverse (11002781), we get a palindrome (29722792).

The spelling of 18720011 in words is "eighteen million, seven hundred twenty thousand, eleven".