18720071 has 4 divisors (see below), whose sum is σ = 18736200. Its totient is φ = 18703944.

The previous prime is 18719983. The next prime is 18720083. The reversal of 18720071 is 17002781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17002781 = 613 ⋅27737.

It is a cyclic number.

It is not a de Polignac number, because 18720071 - 2¹⁴ = 18703687 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18720071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18720571) 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, 6176 + ... + 8693.

It is an arithmetic number, because the mean of its divisors is an integer number (4684050).

Almost surely, 2^18720071 is an apocalyptic number.

18720071 is a deficient number, since it is larger than the sum of its proper divisors (16129).

18720071 is a wasteful number, since it uses less digits than its factorization.

18720071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16128.

The product of its (nonzero) digits is 784, while the sum is 26.

The square root of 18720071 is about 4326.6697354894. The cubic root of 18720071 is about 265.5232145379.

The spelling of 18720071 in words is "eighteen million, seven hundred twenty thousand, seventy-one".