66777812640 has 960 divisors, whose sum is σ = 298911368448. Its totient is φ = 13635993600.

The previous prime is 66777812627. The next prime is 66777812653. The reversal of 66777812640 is 4621877766.

It is an interprime number because it is at equal distance from previous prime (66777812627) and next prime (66777812653).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 60872572 + ... + 60873668.

Almost surely, 2^66777812640 is an apocalyptic number.

66777812640 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 66777812640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149455684224).

66777812640 is an abundant number, since it is smaller than the sum of its proper divisors (232133555808).

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

66777812640 is a wasteful number, since it uses less digits than its factorization.

66777812640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1203 (or 1186 counting only the distinct ones).

The product of its (nonzero) digits is 4741632, while the sum is 54.

The spelling of 66777812640 in words is "sixty-six billion, seven hundred seventy-seven million, eight hundred twelve thousand, six hundred forty".