21505510560 has 96 divisors (see below), whose sum is σ = 68375627712. Its totient is φ = 5681192960.

The previous prime is 21505510489. The next prime is 21505510573. The reversal of 21505510560 is 6501550512.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

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 15 ways as a sum of consecutive naturals, for example, 158001 + ... + 260720.

It is an arithmetic number, because the mean of its divisors is an integer number (712246122).

Almost surely, 2^21505510560 is an apocalyptic number.

21505510560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21505510560 is an abundant number, since it is smaller than the sum of its proper divisors (46870117152).

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

21505510560 is a wasteful number, since it uses less digits than its factorization.

21505510560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418846 (or 418838 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 30.

The spelling of 21505510560 in words is "twenty-one billion, five hundred five million, five hundred ten thousand, five hundred sixty".