18720361 has 4 divisors (see below), whose sum is σ = 20422224. Its totient is φ = 17018500.

The previous prime is 18720343. The next prime is 18720379. The reversal of 18720361 is 16302781.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (18720343) and next prime (18720379).

It is a cyclic number.

It is not a de Polignac number, because 18720361 - 2⁹ = 18719849 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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 850915 + ... + 850936.

It is an arithmetic number, because the mean of its divisors is an integer number (5105556).

Almost surely, 2^18720361 is an apocalyptic number.

18720361 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18720361 is a deficient number, since it is larger than the sum of its proper divisors (1701863).

18720361 is a wasteful number, since it uses less digits than its factorization.

18720361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1701862.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 18720361 is about 4326.7032484329. The cubic root of 18720361 is about 265.5245856391.

The spelling of 18720361 in words is "eighteen million, seven hundred twenty thousand, three hundred sixty-one".