66780358205624 has 96 divisors (see below), whose sum is σ = 148152314921760. Its totient is φ = 28130363654400.

The previous prime is 66780358205581. The next prime is 66780358205647. The reversal of 66780358205624 is 42650285308766.

It is a happy number.

It is a Cunningham number, because it is equal to 8171925²-1.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31666214 + ... + 33709194.

It is an arithmetic number, because the mean of its divisors is an integer number (1543253280435).

Almost surely, 2^{66780358205624} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66780358205624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (74076157460880).

66780358205624 is an abundant number, since it is smaller than the sum of its proper divisors (81371956716136).

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

66780358205624 is a wasteful number, since it uses less digits than its factorization.

66780358205624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2044429 (or 2044418 counting only the distinct ones).

The product of its (nonzero) digits is 116121600, while the sum is 62.

The spelling of 66780358205624 in words is "sixty-six trillion, seven hundred eighty billion, three hundred fifty-eight million, two hundred five thousand, six hundred twenty-four".