21856214016 has 1056 divisors, whose sum is σ = 87033199680. Its totient is φ = 5350883328.

The previous prime is 21856213993. The next prime is 21856214027. The reversal of 21856214016 is 61041265812.

It is a happy number.

21856214016 is a `hidden beast` number, since 2 + 18 + 5 + 621 + 4 + 0 + 16 = 666.

It is a super-2 number, since 2×21856214016² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 299400156 + ... + 299400228.

Almost surely, 2^21856214016 is an apocalyptic number.

21856214016 is a gapful number since it is divisible by the number (26) 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 21856214016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43516599840).

21856214016 is an abundant number, since it is smaller than the sum of its proper divisors (65176985664).

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

21856214016 is a wasteful number, since it uses less digits than its factorization.

21856214016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

Adding to 21856214016 its reverse (61041265812), we get a palindrome (82897479828).

The spelling of 21856214016 in words is "twenty-one billion, eight hundred fifty-six million, two hundred fourteen thousand, sixteen".