21857946240 has 768 divisors, whose sum is σ = 81282216960. Its totient is φ = 4984012800.

The previous prime is 21857946239. The next prime is 21857946241. The reversal of 21857946240 is 4264975812.

It is an interprime number because it is at equal distance from previous prime (21857946239) and next prime (21857946241).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21857946240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21857946241) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 412414054 + ... + 412414106.

It is an arithmetic number, because the mean of its divisors is an integer number (105836220).

Almost surely, 2^21857946240 is an apocalyptic number.

21857946240 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 21857946240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40641108480).

21857946240 is an abundant number, since it is smaller than the sum of its proper divisors (59424270720).

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

21857946240 is a wasteful number, since it uses less digits than its factorization.

21857946240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 48.

The spelling of 21857946240 in words is "twenty-one billion, eight hundred fifty-seven million, nine hundred forty-six thousand, two hundred forty".