21003403440 has 80 divisors (see below), whose sum is σ = 68940596448. Its totient is φ = 5271441408.

The previous prime is 21003403403. The next prime is 21003403483. The reversal of 21003403440 is 4430430012.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×21003403440² (a number of 21 digits) contains 22 as substring.

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, 2569867 + ... + 2578026.

Almost surely, 2^21003403440 is an apocalyptic number.

21003403440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21003403440 is an abundant number, since it is smaller than the sum of its proper divisors (47937193008).

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

21003403440 is a wasteful number, since it uses less digits than its factorization.

21003403440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5147926 (or 5147920 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 21.

Adding to 21003403440 its reverse (4430430012), we get a palindrome (25433833452).

The spelling of 21003403440 in words is "twenty-one billion, three million, four hundred three thousand, four hundred forty".