21828521520 has 200 divisors, whose sum is σ = 81645826416. Its totient is φ = 5373153792.

The previous prime is 21828521513. The next prime is 21828521551. The reversal of 21828521520 is 2512582812.

21828521520 is a `hidden beast` number, since 2 + 1 + 82 + 8 + 52 + 1 + 520 = 666.

It is a super-2 number, since 2×21828521520² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 45322 + ... + 213801.

Almost surely, 2^21828521520 is an apocalyptic number.

21828521520 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 21828521520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40822913208).

21828521520 is an abundant number, since it is smaller than the sum of its proper divisors (59817304896).

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

21828521520 is a wasteful number, since it uses less digits than its factorization.

21828521520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259161 (or 259146 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 36.

The spelling of 21828521520 in words is "twenty-one billion, eight hundred twenty-eight million, five hundred twenty-one thousand, five hundred twenty".