18942221 has 8 divisors (see below), whose sum is σ = 20076000. Its totient is φ = 17822160.

The previous prime is 18942211. The next prime is 18942223. The reversal of 18942221 is 12224981.

18942221 is nontrivially palindromic in base 5.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18942221 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 (18942223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 515 + ... + 6176.

It is an arithmetic number, because the mean of its divisors is an integer number (2509500).

Almost surely, 2^18942221 is an apocalyptic number.

It is an amenable number.

18942221 is a deficient number, since it is larger than the sum of its proper divisors (1133779).

18942221 is a wasteful number, since it uses less digits than its factorization.

18942221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6859.

The product of its digits is 2304, while the sum is 29.

The square root of 18942221 is about 4352.2661913077. The cubic root of 18942221 is about 266.5694032439.

The spelling of 18942221 in words is "eighteen million, nine hundred forty-two thousand, two hundred twenty-one".