221102406 has 48 divisors (see below), whose sum is σ = 571564080. Its totient is φ = 63171360.

The previous prime is 221102389. The next prime is 221102407. The reversal of 221102406 is 604201122.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221102407) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 39135 + ... + 44426.

It is an arithmetic number, because the mean of its divisors is an integer number (11907585).

Almost surely, 2^221102406 is an apocalyptic number.

221102406 is an abundant number, since it is smaller than the sum of its proper divisors (350461674).

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

221102406 is a wasteful number, since it uses less digits than its factorization.

221102406 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83586 (or 83573 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 221102406 is about 14869.5126349185. The cubic root of 221102406 is about 604.6877299320.

Adding to 221102406 its reverse (604201122), we get a palindrome (825303528).

The spelling of 221102406 in words is "two hundred twenty-one million, one hundred two thousand, four hundred six".