66999711744 has 432 divisors, whose sum is σ = 232458932160. Its totient is φ = 18517524480.

The previous prime is 66999711683. The next prime is 66999711773. The reversal of 66999711744 is 44711799966.

66999711744 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×66999711744² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 27997012 + ... + 27999404.

It is an arithmetic number, because the mean of its divisors is an integer number (538099380).

Almost surely, 2^66999711744 is an apocalyptic number.

66999711744 is a gapful number since it is divisible by the number (64) 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 66999711744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116229466080).

66999711744 is an abundant number, since it is smaller than the sum of its proper divisors (165459220416).

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

66999711744 is a wasteful number, since it uses less digits than its factorization.

66999711744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2466 (or 2436 counting only the distinct ones).

The product of its digits is 20575296, while the sum is 63.

The spelling of 66999711744 in words is "sixty-six billion, nine hundred ninety-nine million, seven hundred eleven thousand, seven hundred forty-four".