18972871 has 4 divisors (see below), whose sum is σ = 19009672. Its totient is φ = 18936072.

The previous prime is 18972869. The next prime is 18972881. The reversal of 18972871 is 17827981.

It is a happy number.

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 18972871 - 2¹ = 18972869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18972841) 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, 17616 + ... + 18661.

It is an arithmetic number, because the mean of its divisors is an integer number (4752418).

Almost surely, 2^18972871 is an apocalyptic number.

18972871 is a deficient number, since it is larger than the sum of its proper divisors (36801).

18972871 is an equidigital number, since it uses as much as digits as its factorization.

18972871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36800.

The product of its digits is 56448, while the sum is 43.

The square root of 18972871 is about 4355.7859221959. The cubic root of 18972871 is about 266.7131025037.

The spelling of 18972871 in words is "eighteen million, nine hundred seventy-two thousand, eight hundred seventy-one".