66640772520 has 512 divisors, whose sum is σ = 274475520000. Its totient is φ = 14039350272.

The previous prime is 66640772507. The next prime is 66640772563. The reversal of 66640772520 is 2527704666.

66640772520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 5308411 + ... + 5320949.

It is an arithmetic number, because the mean of its divisors is an integer number (536085000).

Almost surely, 2^66640772520 is an apocalyptic number.

66640772520 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 66640772520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137237760000).

66640772520 is an abundant number, since it is smaller than the sum of its proper divisors (207834747480).

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

66640772520 is a wasteful number, since it uses less digits than its factorization.

66640772520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12622 (or 12612 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 45.

It can be divided in two parts, 66640 and 772520, that added together give a triangular number (839160 = T₁₂₉₅).

The spelling of 66640772520 in words is "sixty-six billion, six hundred forty million, seven hundred seventy-two thousand, five hundred twenty".