64526660640 has 720 divisors, whose sum is σ = 261246125448. Its totient is φ = 14940536832.

The previous prime is 64526660617. The next prime is 64526660641. The reversal of 64526660640 is 4606662546.

It can be written as a sum of positive squares in 12 ways, for example, as 167029776 + 64359630864 = 12924^2 + 253692^2 .

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (64526660641) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 37233214 + ... + 37234946.

Almost surely, 2^64526660640 is an apocalyptic number.

64526660640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64526660640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130623062724).

64526660640 is an abundant number, since it is smaller than the sum of its proper divisors (196719464808).

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

64526660640 is a wasteful number, since it uses less digits than its factorization.

64526660640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1803 (or 1773 counting only the distinct ones).

The product of its (nonzero) digits is 1244160, while the sum is 45.

The spelling of 64526660640 in words is "sixty-four billion, five hundred twenty-six million, six hundred sixty thousand, six hundred forty".