18221340 has 24 divisors (see below), whose sum is σ = 51019920. Its totient is φ = 4859008.

The previous prime is 18221339. The next prime is 18221341. The reversal of 18221340 is 4312281.

It is an interprime number because it is at equal distance from previous prime (18221339) and next prime (18221341).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18221341) 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, 151785 + ... + 151904.

It is an arithmetic number, because the mean of its divisors is an integer number (2125830).

Almost surely, 2^18221340 is an apocalyptic number.

18221340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18221340 is an abundant number, since it is smaller than the sum of its proper divisors (32798580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18221340 is a wasteful number, since it uses less digits than its factorization.

18221340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303701 (or 303699 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 18221340 is about 4268.6461553987. The cubic root of 18221340 is about 263.1439789554.

The spelling of 18221340 in words is "eighteen million, two hundred twenty-one thousand, three hundred forty".