18720667 has 4 divisors (see below), whose sum is σ = 21395056. Its totient is φ = 16046280.

The previous prime is 18720661. The next prime is 18720673. The reversal of 18720667 is 76602781.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (18720661) and next prime (18720673).

It is a cyclic number.

It is not a de Polignac number, because 18720667 - 2⁷ = 18720539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18720661) 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, 1337184 + ... + 1337197.

It is an arithmetic number, because the mean of its divisors is an integer number (5348764).

Almost surely, 2^18720667 is an apocalyptic number.

18720667 is a deficient number, since it is larger than the sum of its proper divisors (2674389).

18720667 is an equidigital number, since it uses as much as digits as its factorization.

18720667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2674388.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 18720667 is about 4326.7386100850. The cubic root of 18720667 is about 265.5260323719.

The spelling of 18720667 in words is "eighteen million, seven hundred twenty thousand, six hundred sixty-seven".