21643016252 has 48 divisors (see below), whose sum is σ = 44691410400. Its totient is φ = 9041276160.

The previous prime is 21643016207. The next prime is 21643016257. The reversal of 21643016252 is 25261034612.

It is a super-2 number, since 2×21643016252² (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 (21643016257) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 48374 + ... + 213602.

It is an arithmetic number, because the mean of its divisors is an integer number (931071050).

Almost surely, 2^21643016252 is an apocalyptic number.

21643016252 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21643016252 is an abundant number, since it is smaller than the sum of its proper divisors (23048394148).

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

21643016252 is a wasteful number, since it uses less digits than its factorization.

21643016252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165486 (or 165484 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The spelling of 21643016252 in words is "twenty-one billion, six hundred forty-three million, sixteen thousand, two hundred fifty-two".