20421406 has 16 divisors (see below), whose sum is σ = 31648320. Its totient is φ = 9877120.

The previous prime is 20421389. The next prime is 20421407. The reversal of 20421406 is 60412402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421407) 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, 7146 + ... + 9586.

It is an arithmetic number, because the mean of its divisors is an integer number (1978020).

Almost surely, 2^20421406 is an apocalyptic number.

20421406 is a deficient number, since it is larger than the sum of its proper divisors (11226914).

20421406 is a wasteful number, since it uses less digits than its factorization.

20421406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2579.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 20421406 is about 4519.0049789749. The cubic root of 20421406 is about 273.3349794996.

Adding to 20421406 its reverse (60412402), we get a palindrome (80833808).

The spelling of 20421406 in words is "twenty million, four hundred twenty-one thousand, four hundred six".