221301666 has 16 divisors (see below), whose sum is σ = 491781600. Its totient is φ = 73767204.

The previous prime is 221301643. The next prime is 221301781. The reversal of 221301666 is 666103122.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2049036 + ... + 2049143.

It is an arithmetic number, because the mean of its divisors is an integer number (30736350).

Almost surely, 2^221301666 is an apocalyptic number.

221301666 is an abundant number, since it is smaller than the sum of its proper divisors (270479934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221301666 is a wasteful number, since it uses less digits than its factorization.

221301666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4098190 (or 4098184 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 221301666 is about 14876.2114128564. The cubic root of 221301666 is about 604.8693258746.

Adding to 221301666 its reverse (666103122), we get a palindrome (887404788).

The spelling of 221301666 in words is "two hundred twenty-one million, three hundred one thousand, six hundred sixty-six".