221685516869 has 2 divisors, whose sum is σ = 221685516870. Its totient is φ = 221685516868.

The previous prime is 221685516809. The next prime is 221685516881. The reversal of 221685516869 is 968615586122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142027228225 + 79658288644 = 376865^2 + 282238^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221685516869 is a prime.

It is a super-2 number, since 2×221685516869² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221685516809) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110842758434 + 110842758435.

It is an arithmetic number, because the mean of its divisors is an integer number (110842758435).

Almost surely, 2^221685516869 is an apocalyptic number.

It is an amenable number.

221685516869 is a deficient number, since it is larger than the sum of its proper divisors (1).

221685516869 is an equidigital number, since it uses as much as digits as its factorization.

221685516869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12441600, while the sum is 59.

The spelling of 221685516869 in words is "two hundred twenty-one billion, six hundred eighty-five million, five hundred sixteen thousand, eight hundred sixty-nine".