21242020440 has 64 divisors (see below), whose sum is σ = 63929772000. Its totient is φ = 5646431232.

The previous prime is 21242020433. The next prime is 21242020451. The reversal of 21242020440 is 4402024212.

It is a congruent number.

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, 245215 + ... + 320334.

Almost surely, 2^21242020440 is an apocalyptic number.

21242020440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21242020440 is an abundant number, since it is smaller than the sum of its proper divisors (42687751560).

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

21242020440 is a wasteful number, since it uses less digits than its factorization.

21242020440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565876 (or 565872 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 21.

Adding to 21242020440 its reverse (4402024212), we get a palindrome (25644044652).

The spelling of 21242020440 in words is "twenty-one billion, two hundred forty-two million, twenty thousand, four hundred forty".