221565710100661 has 8 divisors (see below), whose sum is σ = 237447623516544. Its totient is φ = 206204515157520.

The previous prime is 221565710100653. The next prime is 221565710100673. The reversal of 221565710100661 is 166001017565122.

It is a happy number.

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 221565710100661 - 2³ = 221565710100653 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 (221565710100961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 130179617305 + ... + 130179619006.

It is an arithmetic number, because the mean of its divisors is an integer number (29680952939568).

Almost surely, 2^{221565710100661} is an apocalyptic number.

It is an amenable number.

221565710100661 is a deficient number, since it is larger than the sum of its proper divisors (15881913415883).

221565710100661 is a wasteful number, since it uses less digits than its factorization.

221565710100661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260359236371.

The product of its (nonzero) digits is 151200, while the sum is 43.

Adding to 221565710100661 its reverse (166001017565122), we get a palindrome (387566727665783).

The spelling of 221565710100661 in words is "two hundred twenty-one trillion, five hundred sixty-five billion, seven hundred ten million, one hundred thousand, six hundred sixty-one".