21868841520 has 120 divisors (see below), whose sum is σ = 73558635696. Its totient is φ = 5822498304.

The previous prime is 21868841509. The next prime is 21868841557. The reversal of 21868841520 is 2514886812.

21868841520 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 88 + 41 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 439342 + ... + 486578.

Almost surely, 2^21868841520 is an apocalyptic number.

21868841520 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 21868841520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36779317848).

21868841520 is an abundant number, since it is smaller than the sum of its proper divisors (51689794176).

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

21868841520 is a wasteful number, since it uses less digits than its factorization.

21868841520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47899 (or 47890 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 45.

The spelling of 21868841520 in words is "twenty-one billion, eight hundred sixty-eight million, eight hundred forty-one thousand, five hundred twenty".