18997211 has 4 divisors (see below), whose sum is σ = 20114712. Its totient is φ = 17879712.

The previous prime is 18997201. The next prime is 18997213. The reversal of 18997211 is 11279981.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18997211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18997213) 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, 558725 + ... + 558758.

It is an arithmetic number, because the mean of its divisors is an integer number (5028678).

Almost surely, 2^18997211 is an apocalyptic number.

18997211 is a deficient number, since it is larger than the sum of its proper divisors (1117501).

18997211 is a wasteful number, since it uses less digits than its factorization.

18997211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1117500.

The product of its digits is 9072, while the sum is 38.

The square root of 18997211 is about 4358.5790115587. The cubic root of 18997211 is about 266.8271077908.

The spelling of 18997211 in words is "eighteen million, nine hundred ninety-seven thousand, two hundred eleven".