21166500560 has 40 divisors (see below), whose sum is σ = 49259946120. Its totient is φ = 8458371072.

The previous prime is 21166500529. The next prime is 21166500577. The reversal of 21166500560 is 6500566112.

It can be written as a sum of positive squares in 4 ways, for example, as 7753154704 + 13413345856 = 88052^2 + 115816^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45425 + ... + 210704.

It is an arithmetic number, because the mean of its divisors is an integer number (1231498653).

Almost surely, 2^21166500560 is an apocalyptic number.

21166500560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21166500560 is an abundant number, since it is smaller than the sum of its proper divisors (28093445560).

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

21166500560 is a wasteful number, since it uses less digits than its factorization.

21166500560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257175 (or 257169 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 32.

The spelling of 21166500560 in words is "twenty-one billion, one hundred sixty-six million, five hundred thousand, five hundred sixty".