21404321040 has 160 divisors (see below), whose sum is σ = 67011960960. Its totient is φ = 5651402752.

The previous prime is 21404321033. The next prime is 21404321221. The reversal of 21404321040 is 4012340412.

It is a junction number, because it is equal to n+sod(n) for n = 21404320998 and 21404321016.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19300006 + ... + 19301114.

It is an arithmetic number, because the mean of its divisors is an integer number (418824756).

Almost surely, 2^21404321040 is an apocalyptic number.

21404321040 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 21404321040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33505980480).

21404321040 is an abundant number, since it is smaller than the sum of its proper divisors (45607639920).

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

21404321040 is a wasteful number, since it uses less digits than its factorization.

21404321040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1849 (or 1843 counting only the distinct ones).

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

Adding to 21404321040 its reverse (4012340412), we get a palindrome (25416661452).

The spelling of 21404321040 in words is "twenty-one billion, four hundred four million, three hundred twenty-one thousand, forty".