661065562312221 has 8 divisors (see below), whose sum is σ = 961549908817824. Its totient is φ = 400645795340720.

The previous prime is 661065562312193. The next prime is 661065562312271. The reversal of 661065562312221 is 122213265560166.

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 661065562312221 - 2⁹ = 661065562311709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661065562312271) 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, 10016144883486 + ... + 10016144883551.

It is an arithmetic number, because the mean of its divisors is an integer number (120193738602228).

Almost surely, 2^{661065562312221} is an apocalyptic number.

It is an amenable number.

661065562312221 is a deficient number, since it is larger than the sum of its proper divisors (300484346505603).

661065562312221 is a wasteful number, since it uses less digits than its factorization.

661065562312221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20032289767051.

The product of its (nonzero) digits is 1555200, while the sum is 48.

The spelling of 661065562312221 in words is "six hundred sixty-one trillion, sixty-five billion, five hundred sixty-two million, three hundred twelve thousand, two hundred twenty-one".