221411712640666 has 4 divisors (see below), whose sum is σ = 332117568961002. Its totient is φ = 110705856320332.

The previous prime is 221411712640543. The next prime is 221411712640697. The reversal of 221411712640666 is 666046217114122.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 221011186938025 + 400525702641 = 14866445^2 + 632871^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55352928160165 + ... + 55352928160168.

Almost surely, 2^{221411712640666} is an apocalyptic number.

221411712640666 is a deficient number, since it is larger than the sum of its proper divisors (110705856320336).

221411712640666 is a wasteful number, since it uses less digits than its factorization.

221411712640666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110705856320335.

The product of its (nonzero) digits is 1161216, while the sum is 49.

Adding to 221411712640666 its reverse (666046217114122), we get a palindrome (887457929754788).

The spelling of 221411712640666 in words is "two hundred twenty-one trillion, four hundred eleven billion, seven hundred twelve million, six hundred forty thousand, six hundred sixty-six".