21765828855 has 32 divisors (see below), whose sum is σ = 36357590016. Its totient is φ = 11098191104.

The previous prime is 21765828817. The next prime is 21765828869. The reversal of 21765828855 is 55882856712.

It is not a de Polignac number, because 21765828855 - 2⁸ = 21765828599 is a prime.

It is a super-2 number, since 2×21765828855² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21765828795 and 21765828804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 728134 + ... + 757436.

It is an arithmetic number, because the mean of its divisors is an integer number (1136174688).

Almost surely, 2^21765828855 is an apocalyptic number.

21765828855 is a deficient number, since it is larger than the sum of its proper divisors (14591761161).

21765828855 is a wasteful number, since it uses less digits than its factorization.

21765828855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31487.

The product of its digits is 10752000, while the sum is 57.

The spelling of 21765828855 in words is "twenty-one billion, seven hundred sixty-five million, eight hundred twenty-eight thousand, eight hundred fifty-five".