66651866981280 has 144 divisors (see below), whose sum is σ = 259942281266304. Its totient is φ = 15234712450560.

The previous prime is 66651866981243. The next prime is 66651866981309. The reversal of 66651866981280 is 8218966815666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 66651866981199 and 66651866981208.

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, 3306134116 + ... + 3306154275.

It is an arithmetic number, because the mean of its divisors is an integer number (1805154731016).

Almost surely, 2^{66651866981280} is an apocalyptic number.

66651866981280 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66651866981280 is an abundant number, since it is smaller than the sum of its proper divisors (193290414285024).

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

66651866981280 is a wasteful number, since it uses less digits than its factorization.

66651866981280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6612288419 (or 6612288408 counting only the distinct ones).

The product of its (nonzero) digits is 358318080, while the sum is 72.

The spelling of 66651866981280 in words is "sixty-six trillion, six hundred fifty-one billion, eight hundred sixty-six million, nine hundred eighty-one thousand, two hundred eighty".