21104065872 has 60 divisors (see below), whose sum is σ = 59135405940. Its totient is φ = 7025954304.

The previous prime is 21104065859. The next prime is 21104065907. The reversal of 21104065872 is 27856040112.

21104065872 is a `hidden beast` number, since 21 + 10 + 40 + 6 + 587 + 2 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15061180176 + 6042885696 = 122724^2 + 77736^2 .

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

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 11 ways as a sum of consecutive naturals, for example, 25918 + ... + 207074.

It is an arithmetic number, because the mean of its divisors is an integer number (985590099).

Almost surely, 2^21104065872 is an apocalyptic number.

It is an amenable number.

21104065872 is an abundant number, since it is smaller than the sum of its proper divisors (38031340068).

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

21104065872 is a wasteful number, since it uses less digits than its factorization.

21104065872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181980 (or 181971 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 21104065872 in words is "twenty-one billion, one hundred four million, sixty-five thousand, eight hundred seventy-two".