21765828852 has 18 divisors (see below), whose sum is σ = 55019178578. Its totient is φ = 7255276272.

The previous prime is 21765828817. The next prime is 21765828869. The reversal of 21765828852 is 25882856712.

21765828852 is a `hidden beast` number, since 2 + 1 + 7 + 6 + 582 + 8 + 8 + 52 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19258223076 + 2507605776 = 138774^2 + 50076^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×21765828852² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 302303143 + ... + 302303214.

Almost surely, 2^21765828852 is an apocalyptic number.

It is an amenable number.

21765828852 is an abundant number, since it is smaller than the sum of its proper divisors (33253349726).

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

21765828852 is a wasteful number, since it uses less digits than its factorization.

21765828852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604606367 (or 604606362 counting only the distinct ones).

The product of its digits is 4300800, while the sum is 54.

The spelling of 21765828852 in words is "twenty-one billion, seven hundred sixty-five million, eight hundred twenty-eight thousand, eight hundred fifty-two".