21120403440 has 40 divisors (see below), whose sum is σ = 65473251408. Its totient is φ = 5632107520.

The previous prime is 21120403429. The next prime is 21120403457. The reversal of 21120403440 is 4430402112.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44000601 + ... + 44001080.

Almost surely, 2^21120403440 is an apocalyptic number.

21120403440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120403440 is an abundant number, since it is smaller than the sum of its proper divisors (44352847968).

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

21120403440 is a wasteful number, since it uses less digits than its factorization.

21120403440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88001697 (or 88001691 counting only the distinct ones).

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

Adding to 21120403440 its reverse (4430402112), we get a palindrome (25550805552).

The spelling of 21120403440 in words is "twenty-one billion, one hundred twenty million, four hundred three thousand, four hundred forty".