21245448840 has 256 divisors, whose sum is σ = 81612472320. Its totient is φ = 4295255040.

The previous prime is 21245448799. The next prime is 21245448857. The reversal of 21245448840 is 4884454212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 21245448792 and 21245448801.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 310809 + ... + 372951.

It is an arithmetic number, because the mean of its divisors is an integer number (318798720).

Almost surely, 2^21245448840 is an apocalyptic number.

21245448840 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 21245448840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40806236160).

21245448840 is an abundant number, since it is smaller than the sum of its proper divisors (60367023480).

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

21245448840 is a wasteful number, since it uses less digits than its factorization.

21245448840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62212 (or 62208 counting only the distinct ones).

The product of its (nonzero) digits is 327680, while the sum is 42.

The spelling of 21245448840 in words is "twenty-one billion, two hundred forty-five million, four hundred forty-eight thousand, eight hundred forty".