21064043021504 has 56 divisors (see below), whose sum is σ = 47771122095360. Its totient is φ = 9027280394496.

The previous prime is 21064043021473. The next prime is 21064043021509. The reversal of 21064043021504 is 40512034046012.

It is a tau number, because it is divible by the number of its divisors (56).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21064043021509) 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, 25609157 + ... + 26418875.

Almost surely, 2^{21064043021504} is an apocalyptic number.

It is an amenable number.

21064043021504 is an abundant number, since it is smaller than the sum of its proper divisors (26707079073856).

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

21064043021504 is an equidigital number, since it uses as much as digits as its factorization.

21064043021504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 867805 (or 867795 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

Adding to 21064043021504 its reverse (40512034046012), we get a palindrome (61576077067516).

The spelling of 21064043021504 in words is "twenty-one trillion, sixty-four billion, forty-three million, twenty-one thousand, five hundred four".