221647013003666 has 4 divisors (see below), whose sum is σ = 332470519505502. Its totient is φ = 110823506501832.

The previous prime is 221647013003657. The next prime is 221647013003693. The reversal of 221647013003666 is 666300310746122.

221647013003666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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., 119425227394225 + 102221785609441 = 10928185^2 + 10110479^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 221647013003666.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55411753250915 + ... + 55411753250918.

Almost surely, 2^{221647013003666} is an apocalyptic number.

221647013003666 is a deficient number, since it is larger than the sum of its proper divisors (110823506501836).

221647013003666 is a wasteful number, since it uses less digits than its factorization.

221647013003666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110823506501835.

The product of its (nonzero) digits is 1306368, while the sum is 47.

Adding to 221647013003666 its reverse (666300310746122), we get a palindrome (887947323749788).

The spelling of 221647013003666 in words is "two hundred twenty-one trillion, six hundred forty-seven billion, thirteen million, three thousand, six hundred sixty-six".