20438040 has 128 divisors (see below), whose sum is σ = 72576000. Its totient is φ = 4505088.

The previous prime is 20438027. The next prime is 20438051. The reversal of 20438040 is 4083402.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 20437998 and 20438016.

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 in 31 ways as a sum of consecutive naturals, for example, 23941 + ... + 24779.

It is an arithmetic number, because the mean of its divisors is an integer number (567000).

Almost surely, 2^20438040 is an apocalyptic number.

20438040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20438040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36288000).

20438040 is an abundant number, since it is smaller than the sum of its proper divisors (52137960).

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

20438040 is a wasteful number, since it uses less digits than its factorization.

20438040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 889 (or 885 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 20438040 is about 4520.8450537482. The cubic root of 20438040 is about 273.4091732180.

The spelling of 20438040 in words is "twenty million, four hundred thirty-eight thousand, forty".