18220408 has 8 divisors (see below), whose sum is σ = 34163280. Its totient is φ = 9110200.

The previous prime is 18220403. The next prime is 18220417. The reversal of 18220408 is 80402281.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18220403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1138768 + ... + 1138783.

It is an arithmetic number, because the mean of its divisors is an integer number (4270410).

Almost surely, 2^18220408 is an apocalyptic number.

It is an amenable number.

18220408 is a deficient number, since it is larger than the sum of its proper divisors (15942872).

18220408 is a wasteful number, since it uses less digits than its factorization.

18220408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2277557 (or 2277553 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 18220408 is about 4268.5369859004. The cubic root of 18220408 is about 263.1394923777.

Adding to 18220408 its reverse (80402281), we get a palindrome (98622689).

The spelling of 18220408 in words is "eighteen million, two hundred twenty thousand, four hundred eight".