21015106560 has 1056 divisors, whose sum is σ = 91558871040. Its totient is φ = 4514807808.

The previous prime is 21015106549. The next prime is 21015106613. The reversal of 21015106560 is 6560151012.

It is a happy number.

21015106560 is a `hidden beast` number, since 2 + 1 + 0 + 1 + 5 + 1 + 0 + 656 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 165473217 + ... + 165473343.

Almost surely, 2^21015106560 is an apocalyptic number.

21015106560 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 21015106560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45779435520).

21015106560 is an abundant number, since it is smaller than the sum of its proper divisors (70543764480).

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

21015106560 is a wasteful number, since it uses less digits than its factorization.

21015106560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 163 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

Adding to 21015106560 its reverse (6560151012), we get a palindrome (27575257572).

The spelling of 21015106560 in words is "twenty-one billion, fifteen million, one hundred six thousand, five hundred sixty".