221961218 has 8 divisors (see below), whose sum is σ = 337911312. Its totient is φ = 109324116.

The previous prime is 221961199. The next prime is 221961251. The reversal of 221961218 is 812169122.

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 828080 + ... + 828347.

It is an arithmetic number, because the mean of its divisors is an integer number (42238914).

Almost surely, 2^221961218 is an apocalyptic number.

221961218 is a deficient number, since it is larger than the sum of its proper divisors (115950094).

221961218 is a wasteful number, since it uses less digits than its factorization.

221961218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1656496.

The product of its digits is 3456, while the sum is 32.

The square root of 221961218 is about 14898.3629302014. The cubic root of 221961218 is about 605.4696333022.

The spelling of 221961218 in words is "two hundred twenty-one million, nine hundred sixty-one thousand, two hundred eighteen".