66645425403666 has 192 divisors, whose sum is σ = 154465531234560. Its totient is φ = 20707099200000.

The previous prime is 66645425403659. The next prime is 66645425403679. The reversal of 66645425403666 is 66630452454666.

It is a super-2 number, since 2×66645425403666² (a number of 28 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 10834889691 + ... + 10834895841.

It is an arithmetic number, because the mean of its divisors is an integer number (804507975180).

Almost surely, 2^{66645425403666} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66645425403666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77232765617280).

66645425403666 is an abundant number, since it is smaller than the sum of its proper divisors (87820105830894).

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

66645425403666 is a wasteful number, since it uses less digits than its factorization.

66645425403666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8193 (or 8190 counting only the distinct ones).

The product of its (nonzero) digits is 447897600, while the sum is 63.

The spelling of 66645425403666 in words is "sixty-six trillion, six hundred forty-five billion, four hundred twenty-five million, four hundred three thousand, six hundred sixty-six".