66761072640 has 896 divisors, whose sum is σ = 259884184320. Its totient is φ = 16194207744.

The previous prime is 66761072629. The next prime is 66761072683. The reversal of 66761072640 is 4627016766.

It is a happy number.

66761072640 is a `hidden beast` number, since 6 + 6 + 7 + 610 + 7 + 26 + 4 + 0 = 666.

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 63 ways as a sum of consecutive naturals, for example, 996433887 + ... + 996433953.

Almost surely, 2^66761072640 is an apocalyptic number.

66761072640 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 66761072640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129942092160).

66761072640 is an abundant number, since it is smaller than the sum of its proper divisors (193123111680).

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

66761072640 is a wasteful number, since it uses less digits than its factorization.

66761072640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177 (or 147 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 45.

The spelling of 66761072640 in words is "sixty-six billion, seven hundred sixty-one million, seventy-two thousand, six hundred forty".