18221073 has 24 divisors (see below), whose sum is σ = 26685792. Its totient is φ = 11052288.

The previous prime is 18221041. The next prime is 18221081. The reversal of 18221073 is 37012281.

It is not a de Polignac number, because 18221073 - 2⁵ = 18221041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18221003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41865 + ... + 42297.

It is an arithmetic number, because the mean of its divisors is an integer number (1111908).

Almost surely, 2^18221073 is an apocalyptic number.

18221073 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18221073 is a deficient number, since it is larger than the sum of its proper divisors (8464719).

18221073 is a wasteful number, since it uses less digits than its factorization.

18221073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545 (or 532 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 18221073 is about 4268.6148807312. The cubic root of 18221073 is about 263.1426936532.

The spelling of 18221073 in words is "eighteen million, two hundred twenty-one thousand, seventy-three".