101666511705221 has 4 divisors (see below), whose sum is σ = 101973661287744. Its totient is φ = 101359362122700.

The previous prime is 101666511705169. The next prime is 101666511705247. The reversal of 101666511705221 is 122507115666101.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 101666511705221 - 2¹⁴ = 101666511688837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (101666511705281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153574790765 + ... + 153574791426.

It is an arithmetic number, because the mean of its divisors is an integer number (25493415321936).

Almost surely, 2^{101666511705221} is an apocalyptic number.

It is an amenable number.

101666511705221 is a deficient number, since it is larger than the sum of its proper divisors (307149582523).

101666511705221 is an equidigital number, since it uses as much as digits as its factorization.

101666511705221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307149582522.

The product of its (nonzero) digits is 151200, while the sum is 44.

The spelling of 101666511705221 in words is "one hundred one trillion, six hundred sixty-six billion, five hundred eleven million, seven hundred five thousand, two hundred twenty-one".