66251371648 has 128 divisors (see below), whose sum is σ = 164812579200. Its totient is φ = 25771499520.

The previous prime is 66251371631. The next prime is 66251371649. The reversal of 66251371648 is 84617315266.

66251371648 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (66251371649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6667548 + ... + 6677476.

It is an arithmetic number, because the mean of its divisors is an integer number (1287598275).

Almost surely, 2^66251371648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66251371648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82406289600).

66251371648 is an abundant number, since it is smaller than the sum of its proper divisors (98561207552).

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

66251371648 is a wasteful number, since it uses less digits than its factorization.

66251371648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10638 (or 10626 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 49.

The spelling of 66251371648 in words is "sixty-six billion, two hundred fifty-one million, three hundred seventy-one thousand, six hundred forty-eight".