21200240440 has 16 divisors (see below), whose sum is σ = 47700541080. Its totient is φ = 8480096160.

The previous prime is 21200240419. The next prime is 21200240443. The reversal of 21200240440 is 4404200212.

It is a super-2 number, since 2×21200240440² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200240443) 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, 265002966 + ... + 265003045.

Almost surely, 2^21200240440 is an apocalyptic number.

21200240440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200240440 is an abundant number, since it is smaller than the sum of its proper divisors (26500300640).

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

21200240440 is a wasteful number, since it uses less digits than its factorization.

21200240440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530006022 (or 530006018 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

Adding to 21200240440 its reverse (4404200212), we get a palindrome (25604440652).

The spelling of 21200240440 in words is "twenty-one billion, two hundred million, two hundred forty thousand, four hundred forty".