21571217512 has 32 divisors (see below), whose sum is σ = 44379112680. Its totient is φ = 9768096000.

The previous prime is 21571217477. The next prime is 21571217513.

21571217512 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 4 ways, for example, as 14355394596 + 7215822916 = 119814^2 + 84946^2 .

It is not an unprimeable number, because it can be changed into a prime (21571217513) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1951239 + ... + 1962262.

Almost surely, 2^21571217512 is an apocalyptic number.

It is an amenable number.

21571217512 is an abundant number, since it is smaller than the sum of its proper divisors (22807895168).

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

21571217512 is a wasteful number, since it uses less digits than its factorization.

21571217512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3913573 (or 3913569 counting only the distinct ones).

The product of its digits is 9800, while the sum is 34.

The spelling of 21571217512 in words is "twenty-one billion, five hundred seventy-one million, two hundred seventeen thousand, five hundred twelve".