21440520040 has 16 divisors (see below), whose sum is σ = 48241170180. Its totient is φ = 8576208000.

The previous prime is 21440520011. The next prime is 21440520043. The reversal of 21440520040 is 4002504412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21385552644 + 54967396 = 146238^2 + 7414^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21440519993 and 21440520020.

It is not an unprimeable number, because it can be changed into a prime (21440520043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 268006461 + ... + 268006540.

Almost surely, 2^21440520040 is an apocalyptic number.

21440520040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21440520040 is an abundant number, since it is smaller than the sum of its proper divisors (26800650140).

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

21440520040 is a wasteful number, since it uses less digits than its factorization.

21440520040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 536013012 (or 536013008 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 22.

The spelling of 21440520040 in words is "twenty-one billion, four hundred forty million, five hundred twenty thousand, forty".