21755477248 has 72 divisors (see below), whose sum is σ = 44464419720. Its totient is φ = 10620272640.

The previous prime is 21755477213. The next prime is 21755477257. The reversal of 21755477248 is 84277455712.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3268180224 + 18487297024 = 57168^2 + 135968^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21755477195 and 21755477204.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 2134308 + ... + 2144476.

It is an arithmetic number, because the mean of its divisors is an integer number (617561385).

Almost surely, 2^21755477248 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21755477248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22232209860).

21755477248 is an abundant number, since it is smaller than the sum of its proper divisors (22708942472).

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

21755477248 is a wasteful number, since it uses less digits than its factorization.

21755477248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10383 (or 10369 counting only the distinct ones).

The product of its digits is 4390400, while the sum is 52.

The spelling of 21755477248 in words is "twenty-one billion, seven hundred fifty-five million, four hundred seventy-seven thousand, two hundred forty-eight".