21571017512 has 48 divisors (see below), whose sum is σ = 44740276980. Its totient is φ = 9742487040.

The previous prime is 21571017499. The next prime is 21571017529.

21571017512 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 21423005956 + 148011556 = 146366^2 + 12166^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 81008 + ... + 222944.

Almost surely, 2^21571017512 is an apocalyptic number.

21571017512 is a gapful number since it is divisible by the number (22) 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 21571017512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22370138490).

21571017512 is an abundant number, since it is smaller than the sum of its proper divisors (23169259468).

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

21571017512 is a wasteful number, since it uses less digits than its factorization.

21571017512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142122 (or 142107 counting only the distinct ones).

The product of its (nonzero) digits is 4900, while the sum is 32.

The spelling of 21571017512 in words is "twenty-one billion, five hundred seventy-one million, seventeen thousand, five hundred twelve".