18220001 has 4 divisors (see below), whose sum is σ = 18230832. Its totient is φ = 18209172.

The previous prime is 18219989. The next prime is 18220049. The reversal of 18220001 is 10002281.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10002281 = 197 ⋅50773.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18220001 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18220051) 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, 2291 + ... + 6456.

It is an arithmetic number, because the mean of its divisors is an integer number (4557708).

Almost surely, 2^18220001 is an apocalyptic number.

It is an amenable number.

18220001 is a deficient number, since it is larger than the sum of its proper divisors (10831).

18220001 is an equidigital number, since it uses as much as digits as its factorization.

18220001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10830.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 18220001 is about 4268.4893112201. The cubic root of 18220001 is about 263.1375330625.

Adding to 18220001 its reverse (10002281), we get a palindrome (28222282).

The spelling of 18220001 in words is "eighteen million, two hundred twenty thousand, one".