21445053840 has 360 divisors, whose sum is σ = 84124579968. Its totient is φ = 4881461760.

The previous prime is 21445053809. The next prime is 21445053841. The reversal of 21445053840 is 4835054412.

It is a happy number.

21445053840 is a `hidden beast` number, since 2 + 144 + 505 + 3 + 8 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (360).

It is a super-3 number, since 3×21445053840³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21445053795 and 21445053804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445053841) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 9559759 + ... + 9562001.

Almost surely, 2^21445053840 is an apocalyptic number.

21445053840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21445053840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42062289984).

21445053840 is an abundant number, since it is smaller than the sum of its proper divisors (62679526128).

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

21445053840 is a wasteful number, since it uses less digits than its factorization.

21445053840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2547 (or 2531 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The spelling of 21445053840 in words is "twenty-one billion, four hundred forty-five million, fifty-three thousand, eight hundred forty".