21171022512 has 20 divisors (see below), whose sum is σ = 54691808280. Its totient is φ = 7057007488.

The previous prime is 21171022501. The next prime is 21171022513. The reversal of 21171022512 is 21522017112.

It is a happy number.

It is a super-2 number, since 2×21171022512² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21171022513) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 220531437 + ... + 220531532.

It is an arithmetic number, because the mean of its divisors is an integer number (2734590414).

Almost surely, 2^21171022512 is an apocalyptic number.

It is an amenable number.

21171022512 is an abundant number, since it is smaller than the sum of its proper divisors (33520785768).

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

21171022512 is a wasteful number, since it uses less digits than its factorization.

21171022512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441062980 (or 441062974 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 24.

Adding to 21171022512 its reverse (21522017112), we get a palindrome (42693039624).

The spelling of 21171022512 in words is "twenty-one billion, one hundred seventy-one million, twenty-two thousand, five hundred twelve".