221320242 has 64 divisors (see below), whose sum is σ = 577825920. Its totient is φ = 61905600.

The previous prime is 221320223. The next prime is 221320243. The reversal of 221320242 is 242023122.

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

It is not an unprimeable number, because it can be changed into a prime (221320243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6609 + ... + 22052.

It is an arithmetic number, because the mean of its divisors is an integer number (9028530).

Almost surely, 2^221320242 is an apocalyptic number.

221320242 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

221320242 is an abundant number, since it is smaller than the sum of its proper divisors (356505678).

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

221320242 is a wasteful number, since it uses less digits than its factorization.

221320242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28696 (or 28690 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

The square root of 221320242 is about 14876.8357522694. The cubic root of 221320242 is about 604.8862495885.

Adding to 221320242 its reverse (242023122), we get a palindrome (463343364).

The spelling of 221320242 in words is "two hundred twenty-one million, three hundred twenty thousand, two hundred forty-two".