64771216664 has 128 divisors (see below), whose sum is σ = 155015078400. Its totient is φ = 24641280000.

The previous prime is 64771216637. The next prime is 64771216667. The reversal of 64771216664 is 46661217746.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64771216667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5216864 + ... + 5229264.

It is an arithmetic number, because the mean of its divisors is an integer number (1211055300).

Almost surely, 2^64771216664 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 64771216664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77507539200).

64771216664 is an abundant number, since it is smaller than the sum of its proper divisors (90243861736).

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

64771216664 is a wasteful number, since it uses less digits than its factorization.

64771216664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12625 (or 12621 counting only the distinct ones).

The product of its digits is 2032128, while the sum is 50.

The spelling of 64771216664 in words is "sixty-four billion, seven hundred seventy-one million, two hundred sixteen thousand, six hundred sixty-four".