20404140 has 48 divisors (see below), whose sum is σ = 57788640. Its totient is φ = 5378560.

The previous prime is 20404133. The next prime is 20404159. The reversal of 20404140 is 4140402.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3430 + ... + 7250.

It is an arithmetic number, because the mean of its divisors is an integer number (1203930).

Almost surely, 2^20404140 is an apocalyptic number.

20404140 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 20404140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28894320).

20404140 is an abundant number, since it is smaller than the sum of its proper divisors (37384500).

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

20404140 is a wasteful number, since it uses less digits than its factorization.

20404140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3922 (or 3920 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

The square root of 20404140 is about 4517.0941987078. The cubic root of 20404140 is about 273.2579242038.

Adding to 20404140 its reverse (4140402), we get a palindrome (24544542).

The spelling of 20404140 in words is "twenty million, four hundred four thousand, one hundred forty".