66644444966400 has 1080 divisors, whose sum is σ = 278637419215584. Its totient is φ = 15167338905600.

The previous prime is 66644444966321. The next prime is 66644444966417. The reversal of 66644444966400 is 466944444666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 1315213065 + ... + 1315263735.

Almost surely, 2^{66644444966400} is an apocalyptic number.

66644444966400 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 66644444966400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139318709607792).

66644444966400 is an abundant number, since it is smaller than the sum of its proper divisors (211992974249184).

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

66644444966400 is a wasteful number, since it uses less digits than its factorization.

66644444966400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50952 (or 50921 counting only the distinct ones).

The product of its (nonzero) digits is 286654464, while the sum is 63.

The spelling of 66644444966400 in words is "sixty-six trillion, six hundred forty-four billion, four hundred forty-four million, nine hundred sixty-six thousand, four hundred".