20438406 has 40 divisors (see below), whose sum is σ = 46405920. Its totient is φ = 6722352.

The previous prime is 20438389. The next prime is 20438413. The reversal of 20438406 is 60483402.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 20438406.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 12000 + ... + 13596.

It is an arithmetic number, because the mean of its divisors is an integer number (1160148).

Almost surely, 2^20438406 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20438406, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23202960).

20438406 is an abundant number, since it is smaller than the sum of its proper divisors (25967514).

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

20438406 is a wasteful number, since it uses less digits than its factorization.

20438406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1690 (or 1681 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 20438406 is about 4520.8855327248. The cubic root of 20438406 is about 273.4108052590.

The spelling of 20438406 in words is "twenty million, four hundred thirty-eight thousand, four hundred six".