21545729028 has 48 divisors (see below), whose sum is σ = 55869744000. Its totient is φ = 7180566624.

The previous prime is 21545728987. The next prime is 21545729033. The reversal of 21545729028 is 82092754512.

21545729028 is a `hidden beast` number, since 2 + 1 + 54 + 572 + 9 + 0 + 28 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 683233 + ... + 714071.

It is an arithmetic number, because the mean of its divisors is an integer number (1163953000).

Almost surely, 2^21545729028 is an apocalyptic number.

It is an amenable number.

21545729028 is an abundant number, since it is smaller than the sum of its proper divisors (34324014972).

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

21545729028 is a wasteful number, since it uses less digits than its factorization.

21545729028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37321 (or 37313 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 21545729028 in words is "twenty-one billion, five hundred forty-five million, seven hundred twenty-nine thousand, twenty-eight".