21775534228 has 48 divisors (see below), whose sum is σ = 45008216064. Its totient is φ = 9020826720.

The previous prime is 21775534199. The next prime is 21775534271. The reversal of 21775534228 is 82243557712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 755775 + ... + 784057.

It is an arithmetic number, because the mean of its divisors is an integer number (937671168).

Almost surely, 2^21775534228 is an apocalyptic number.

21775534228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21775534228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22504108032).

21775534228 is an abundant number, since it is smaller than the sum of its proper divisors (23232681836).

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

21775534228 is a wasteful number, since it uses less digits than its factorization.

21775534228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29212 (or 29210 counting only the distinct ones).

The product of its digits is 940800, while the sum is 46.

The spelling of 21775534228 in words is "twenty-one billion, seven hundred seventy-five million, five hundred thirty-four thousand, two hundred twenty-eight".