18221193 has 20 divisors (see below), whose sum is σ = 28161540. Its totient is φ = 11727072.

The previous prime is 18221173. The next prime is 18221213. The reversal of 18221193 is 39112281.

It is an interprime number because it is at equal distance from previous prime (18221173) and next prime (18221213).

It can be written as a sum of positive squares in 2 ways, for example, as 12446784 + 5774409 = 3528^2 + 2403^2 .

It is not a de Polignac number, because 18221193 - 2¹² = 18217097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (18221123) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1530 + ... + 6227.

It is an arithmetic number, because the mean of its divisors is an integer number (1408077).

Almost surely, 2^18221193 is an apocalyptic number.

It is an amenable number.

18221193 is a deficient number, since it is larger than the sum of its proper divisors (9940347).

18221193 is an equidigital number, since it uses as much as digits as its factorization.

18221193 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7798 (or 7789 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 18221193 is about 4268.6289367899. The cubic root of 18221193 is about 263.1432713186.

The spelling of 18221193 in words is "eighteen million, two hundred twenty-one thousand, one hundred ninety-three".