21444212440 has 64 divisors (see below), whose sum is σ = 58044499200. Its totient is φ = 6965336448.

The previous prime is 21444212389. The next prime is 21444212443. The reversal of 21444212440 is 4421244412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 21444212399 and 21444212408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444212443) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2010114 + ... + 2020753.

It is an arithmetic number, because the mean of its divisors is an integer number (906945300).

Almost surely, 2^21444212440 is an apocalyptic number.

21444212440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21444212440 is an abundant number, since it is smaller than the sum of its proper divisors (36600286760).

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

21444212440 is a wasteful number, since it uses less digits than its factorization.

21444212440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4030904 (or 4030900 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 28.

Adding to 21444212440 its reverse (4421244412), we get a palindrome (25865456852).

The spelling of 21444212440 in words is "twenty-one billion, four hundred forty-four million, two hundred twelve thousand, four hundred forty".