21506644352 has 32 divisors (see below), whose sum is σ = 42858768000. Its totient is φ = 10749934080.

The previous prime is 21506644343. The next prime is 21506644409. The reversal of 21506644352 is 25344660512.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 409274 + ... + 458822.

It is an arithmetic number, because the mean of its divisors is an integer number (1339336500).

Almost surely, 2^21506644352 is an apocalyptic number.

It is an amenable number.

21506644352 is a deficient number, since it is larger than the sum of its proper divisors (21352123648).

21506644352 is an equidigital number, since it uses as much as digits as its factorization.

21506644352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52954 (or 52942 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 38.

The spelling of 21506644352 in words is "twenty-one billion, five hundred six million, six hundred forty-four thousand, three hundred fifty-two".