18408406 has 4 divisors (see below), whose sum is σ = 27612612. Its totient is φ = 9204202.

The previous prime is 18408391. The next prime is 18408419. The reversal of 18408406 is 60480481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60480481 = 311 ⋅194471.

It is a super-2 number, since 2×18408406² = 677738822921672, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4602100 + ... + 4602103.

It is an arithmetic number, because the mean of its divisors is an integer number (6903153).

Almost surely, 2^18408406 is an apocalyptic number.

18408406 is a deficient number, since it is larger than the sum of its proper divisors (9204206).

18408406 is an equidigital number, since it uses as much as digits as its factorization.

18408406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9204205.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 18408406 is about 4290.5018354500. The cubic root of 18408406 is about 264.0414210337.

Adding to 18408406 its reverse (60480481), we get a palindrome (78888887).

The spelling of 18408406 in words is "eighteen million, four hundred eight thousand, four hundred six".