21404104040 has 128 divisors (see below), whose sum is σ = 53152848000. Its totient is φ = 7692672000.

The previous prime is 21404104009. The next prime is 21404104049. The reversal of 21404104040 is 4040140412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (21404104049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16451390 + ... + 16452690.

It is an arithmetic number, because the mean of its divisors is an integer number (415256625).

Almost surely, 2^21404104040 is an apocalyptic number.

21404104040 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 21404104040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26576424000).

21404104040 is an abundant number, since it is smaller than the sum of its proper divisors (31748743960).

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

21404104040 is a wasteful number, since it uses less digits than its factorization.

21404104040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1731 (or 1727 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21404104040 its reverse (4040140412), we get a palindrome (25444244452).

The spelling of 21404104040 in words is "twenty-one billion, four hundred four million, one hundred four thousand, forty".