21265446064 has 40 divisors (see below), whose sum is σ = 43780845168. Its totient is φ = 9971619840.

The previous prime is 21265446049. The next prime is 21265446067. The reversal of 21265446064 is 46064456212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21265446067) 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 7 ways as a sum of consecutive naturals, for example, 62682 + ... + 215545.

Almost surely, 2^21265446064 is an apocalyptic number.

It is an amenable number.

21265446064 is an abundant number, since it is smaller than the sum of its proper divisors (22515399104).

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

21265446064 is a wasteful number, since it uses less digits than its factorization.

21265446064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278533 (or 278527 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 40.

The spelling of 21265446064 in words is "twenty-one billion, two hundred sixty-five million, four hundred forty-six thousand, sixty-four".