221861806 has 8 divisors (see below), whose sum is σ = 332859024. Its totient is φ = 110908800.

The previous prime is 221861797. The next prime is 221861807. The reversal of 221861806 is 608168122.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221861807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8206 + ... + 22606.

It is an arithmetic number, because the mean of its divisors is an integer number (41607378).

Almost surely, 2^221861806 is an apocalyptic number.

221861806 is a deficient number, since it is larger than the sum of its proper divisors (110997218).

221861806 is a wasteful number, since it uses less digits than its factorization.

221861806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22106.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 221861806 is about 14895.0262168282. The cubic root of 221861806 is about 605.3792272152.

The spelling of 221861806 in words is "two hundred twenty-one million, eight hundred sixty-one thousand, eight hundred six".