2016500666221 has 2 divisors, whose sum is σ = 2016500666222. Its totient is φ = 2016500666220.

The previous prime is 2016500666177. The next prime is 2016500666291. The reversal of 2016500666221 is 1226660056102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2016226763721 + 273902500 = 1419939^2 + 16550^2 .

It is a cyclic number.

It is not a de Polignac number, because 2016500666221 - 2³¹ = 2014353182573 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2016500666291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1008250333110 + 1008250333111.

It is an arithmetic number, because the mean of its divisors is an integer number (1008250333111).

Almost surely, 2^{2016500666221} is an apocalyptic number.

It is an amenable number.

2016500666221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2016500666221 is an equidigital number, since it uses as much as digits as its factorization.

2016500666221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 2016500666221 in words is "two trillion, sixteen billion, five hundred million, six hundred sixty-six thousand, two hundred twenty-one".