18421407 has 6 divisors (see below), whose sum is σ = 26608712. Its totient is φ = 12280932.

The previous prime is 18421399. The next prime is 18421411. The reversal of 18421407 is 70412481.

It is not a de Polignac number, because 18421407 - 2³ = 18421399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421607) by changing a digit.

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 in 5 ways as a sum of consecutive naturals, for example, 1023403 + ... + 1023420.

Almost surely, 2^18421407 is an apocalyptic number.

18421407 is a deficient number, since it is larger than the sum of its proper divisors (8187305).

18421407 is a wasteful number, since it uses less digits than its factorization.

18421407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2046829 (or 2046826 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 27.

The square root of 18421407 is about 4292.0166588679. The cubic root of 18421407 is about 264.1035664595.

Adding to 18421407 its reverse (70412481), we get a palindrome (88833888).

It can be divided in two parts, 1842 and 1407, that added together give a square (3249 = 57²).

The spelling of 18421407 in words is "eighteen million, four hundred twenty-one thousand, four hundred seven".