21475705168 has 90 divisors (see below), whose sum is σ = 45243996126. Its totient is φ = 9866541312.

The previous prime is 21475705133. The next prime is 21475705169. The reversal of 21475705168 is 86150757412.

It can be written as a sum of positive squares in 3 ways, for example, as 116467264 + 21359237904 = 10792^2 + 146148^2 .

It is a super-2 number, since 2×21475705168² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21475705169) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 67746546 + ... + 67746862.

Almost surely, 2^21475705168 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 21475705168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22621998063).

21475705168 is an abundant number, since it is smaller than the sum of its proper divisors (23768290958).

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

21475705168 is an equidigital number, since it uses as much as digits as its factorization.

21475705168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717 (or 375 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 46.

The spelling of 21475705168 in words is "twenty-one billion, four hundred seventy-five million, seven hundred five thousand, one hundred sixty-eight".