20660006521 has 8 divisors (see below), whose sum is σ = 25757930304. Its totient is φ = 16098706320.

The previous prime is 20660006447. The next prime is 20660006531. The reversal of 20660006521 is 12560006602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20660006521 - 2⁹ = 20660006009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20660006521.

It is not an unprimeable number, because it can be changed into a prime (20660006531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 134155810 + ... + 134155963.

It is an arithmetic number, because the mean of its divisors is an integer number (3219741288).

Almost surely, 2^20660006521 is an apocalyptic number.

It is an amenable number.

20660006521 is a deficient number, since it is larger than the sum of its proper divisors (5097923783).

20660006521 is a wasteful number, since it uses less digits than its factorization.

20660006521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268311791.

The product of its (nonzero) digits is 4320, while the sum is 28.

The spelling of 20660006521 in words is "twenty billion, six hundred sixty million, six thousand, five hundred twenty-one".